scholarly journals Rapid determination of hospital-acquired meticillin-resistant Staphylococcus aureus lineages

2007 ◽  
Vol 56 (5) ◽  
pp. 614-619 ◽  
Author(s):  
Joshua D. Cockfield ◽  
Smriti Pathak ◽  
Jonathan D. Edgeworth ◽  
Jodi A. Lindsay

Multilocus sequence typing (MLST) and multi-strain microarray analysis have shown that most human Staphylococcus aureus strains belong to ten dominant clonal complexes (CCs) or lineages, each with unique surface architecture. Meticillin-resistant S. aureus (MRSA) strains currently belong to six of these lineages (CC1, CC5, CC8, CC22, CC30 and CC45), each of which has independently acquired mobile genetic elements (MGEs) carrying antibiotic resistance genes. MLST and microarrays are expensive and time consuming methods for routine determination of S. aureus lineage. A restriction-modification (RM) test has now been developed that is rapid, simple, inexpensive and accurately determines lineage of hospital-acquired MRSA. The RM test is based on three PCRs for hsdS gene variants, as hsdS genes likely control the independent evolution of S. aureus lineages. The RM test correctly identified 102 MRSA isolates as belonging to one of the six lineages/CCs. Real-time MRSA typing can be used to identify and track changes in local MRSA outbreaks, and provide support for targeting infection control strategies. Simple and accurate typing methods will also support large scale epidemiological studies, and could lead to greater understanding of the carriage, spread and virulence of different MRSA lineages.

2002 ◽  
Vol 46 (4) ◽  
pp. 1147-1152 ◽  
Author(s):  
Xiao Xue Ma ◽  
Teruyo Ito ◽  
Chuntima Tiensasitorn ◽  
Mantana Jamklang ◽  
Piriyaporn Chongtrakool ◽  
...  

ABSTRACT We identified a new type of staphylococcal cassette chromosome mec (SCCmec) from two community-acquired methicillin-resistant Staphylococcus aureus (MRSA) strains. The novel element, designated type IV SCCmec, had a unique combination of the class B mec gene complex and the type 2 ccr gene complex and was much smaller in size (21 to 24 kb) than previously identified SCCmec elements of hospital-acquired MRSA. Consistent with the strains' susceptibilities to various non-β-lactam antibiotics, the type IV SCCmec was devoid of any antibiotic resistance genes other than the mecA gene.


2009 ◽  
Vol 3 (09) ◽  
pp. 681-684 ◽  
Author(s):  
Hare Krishna Tiwari ◽  
Ayan Kumar Das ◽  
Darshan Sapkota ◽  
Kunjukunju Sivrajan ◽  
Vijay Kumar Pahwa

Background: Methicillin resistant Staphylococcus aureus (MRSA) is a major cause of nosocomial and community infections. Its prevalence varies with country and with hospitals within a country. The current study estimates the prevalence of MRSA strains and investigates their antibiogram in western Nepal. Methodology: A total of 162 S. aureus strains were isolated from various clinical specimens, and antibiotic susceptibility tests were performed using disc diffusion, growth on oxacillin screen agar, and oxacillin minimum inhibitory concentration (MIC). Results: One hundred and twelve (69.1%) strains were found to be MRSA, of which 37 (33.1%) were community acquired and 75 (66.9%) were hospital acquired. Of 112 MRSA strains, 45 (40.1%) were multi-drug resistant. All MRSA strains were found resistant to penicillin, and 91.9%, 87.4%, 77%, and 55.5% were resistant to amoxicillin, ampicillin, trimethoprim/sulfamethoxazole, and cephalexin, respectively. However, low resistance was observed with amikacin (19%), ciprofloxacin (26.5%), and norfloxacin (30.6%). All strains were sensitive to vancomycin. Conclusion: The reported rate of MRSA prevalence is alarming. Given the ability of MRSA to spread from person to person, it is necessary to adhere to rational use of antibiotics and to raise awareness among the concerned communities and tourists who visit this area.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Justine Fri ◽  
Henry A. Njom ◽  
Collins N. Ateba ◽  
Roland N. Ndip

Thirty-three (33) isolates of methicillin-resistant Staphylococcus aureus (MRSA) from healthy edible marine fish harvested from two aquaculture settings and the Kariega estuary, South Africa, were characterised in this study. The phenotypic antimicrobial susceptibility profiles to 13 antibiotics were determined, and their antibiotic resistance determinants were assessed. A multiplex PCR was used to determine the epidemiological groups based on the type of SCCmec carriage followed by the detection of staphylococcal enterotoxin-encoding genes sea-sed and the Panton Valentine leucocidin gene (pvl). A high antibiotic resistance percentage (67–81%) was observed for Erythromycin, Ampicillin, Rifampicin, and Clindamycin, while maximum susceptibility to Chloramphenicol (100%), Imipenem (100%), and Ciprofloxacin (94%) was recorded. Nineteen (58%) of the MRSA strains had Vancomycin MICs of ≤2 μg/mL, 4 (12%) with MICs ranging from 4–8 μg/mL, and 10 (30%) with values ≥16 μg/mL. Overall, 27 (82%) isolates were multidrug-resistant (MDR) with Erythromycin-Ampicillin-Rifampicin-Clindamycin (E-AMP-RIP-CD) found to be the dominant antibiotic-resistance phenotype observed in 4 isolates. Resistance genes such as tetM, tetA, ermB, blaZ, and femA were detected in two or more resistant strains. A total of 19 (58%) MRSA strains possessed SCCmec types I, II, or III elements, characteristic of healthcare-associated MRSA (HA-MRSA), while 10 (30%) isolates displayed SCCmec type IVc, characteristic of community-associated MRSA (CA-MRSA). Six (18%) of the multidrug-resistant strains of MRSA were enterotoxigenic, harbouring the see, sea, or sec genes. A prevalence of 18% (6/33) was also recorded for the luk-PVL gene. The findings of this study showed that marine fish contained MDR-MRSA strains that harbour SCCmec types, characteristic of either HA-MRSA or CA-MRSA, but with a low prevalence of enterotoxin and pvl genes. Thus, there is a need for continuous monitoring and implementation of better control strategies within the food chain to minimise contamination of fish with MDR-MRSA and the ultimate spread of the bug.


2020 ◽  
Vol Volume 13 ◽  
pp. 1601-1606
Author(s):  
JeongWoo Kang ◽  
Md Akil Hossain ◽  
Hae-chul Park ◽  
Yong-sang Kim ◽  
Sung-won Park ◽  
...  

mBio ◽  
2012 ◽  
Vol 3 (3) ◽  
Author(s):  
Veronica N. Kos ◽  
Christopher A. Desjardins ◽  
Allison Griggs ◽  
Gustavo Cerqueira ◽  
Andries Van Tonder ◽  
...  

ABSTRACTMethicillin-resistantStaphylococcus aureus(MRSA) strains are leading causes of hospital-acquired infections in the United States, and clonal cluster 5 (CC5) is the predominant lineage responsible for these infections. Since 2002, there have been 12 cases of vancomycin-resistantS. aureus(VRSA) infection in the United States—all CC5 strains. To understand this genetic background and what distinguishes it from other lineages, we generated and analyzed high-quality draft genome sequences for all available VRSA strains. Sequence comparisons show unambiguously that each strain independently acquired Tn1546and that all VRSA strains last shared a common ancestor over 50 years ago, well before the occurrence of vancomycin resistance in this species. In contrast to existing hypotheses on what predisposes this lineage to acquire Tn1546, the barrier posed by restriction systems appears to be intact in most VRSA strains. However, VRSA (and other CC5) strains were found to possess a constellation of traits that appears to be optimized for proliferation in precisely the types of polymicrobic infection where transfer could occur. They lack a bacteriocin operon that would be predicted to limit the occurrence of non-CC5 strains in mixed infection and harbor a cluster of unique superantigens and lipoproteins to confound host immunity. A frameshift indprA, which in other microbes influences uptake of foreign DNA, may also make this lineage conducive to foreign DNA acquisition.IMPORTANCEInvasive methicillin-resistantStaphylococcus aureus(MRSA) infection now ranks among the leading causes of death in the United States. Vancomycin is a key last-line bactericidal drug for treating these infections. However, since 2002, vancomycin resistance has entered this species. Of the now 12 cases of vancomycin-resistantS. aureus(VRSA), each was believed to represent a new acquisition of the vancomycin-resistant transposon Tn1546from enterococcal donors. All acquisitions of Tn1546so far have occurred in MRSA strains of the clonal cluster 5 genetic background, the most common hospital lineage causing hospital-acquired MRSA infection. To understand the nature of these strains, we determined and examined the nucleotide sequences of the genomes of all available VRSA. Genome comparison identified candidate features that position strains of this lineage well for acquiring resistance to antibiotics in mixed infection.


2021 ◽  
Vol 12 ◽  
Author(s):  
Tingting Feng ◽  
Sebastian Leptihn ◽  
Ke Dong ◽  
Belinda Loh ◽  
Yan Zhang ◽  
...  

Phage therapy represents a possible treatment option to cure infections caused by multidrug-resistant bacteria, including methicillin and vancomycin-resistant Staphylococcus aureus, to which most antibiotics have become ineffective. In the present study, we report the isolation and complete characterization of a novel phage named JD219 exhibiting a broad host range able to infect 61 of 138 clinical strains of S. aureus tested, which included MRSA strains as well. The phage JD419 exhibits a unique morphology with an elongated capsid and a flexible tail. To evaluate the potential of JD419 to be used as a therapeutic phage, we tested the ability of the phage particles to remain infectious after treatment exceeding physiological pH or temperature. The activity was retained at pH values of 6.0–8.0 and below 50°C. As phages can contain virulence genes, JD419’s complete genome was sequenced. The 45509 bp genome is predicted to contain 65 ORFs, none of which show homology to any known virulence or antibiotic resistance genes. Genome analysis indicates that JD419 is a temperate phage, despite observing rapid replication and lysis of host strains. Following the recent advances in synthetic biology, JD419 can be modified by gene engineering to remove prophage-related genes, preventing potential lysogeny, in order to be deployed as a therapeutic phage.


2021 ◽  
Author(s):  
Cesar Montelongo ◽  
Carine R Mores ◽  
Catherine Putonti ◽  
Alan Wolfe ◽  
Alaa Abouelfetouh

Antibiotic resistant Staphylococcus infections are a global concern, with increasing cases of resistant Staphylococcus aureus and Staphylococcus haemolyticus found circulating in the Middle East. While extensive surveys have described the prevalence of resistant infections in Europe, Asia, and North America, the population structure of resistant staphylococcal Middle Eastern clinical isolates is poorly characterized. We performed whole genome sequencing of 56 S. aureus and 10 S. haemolyticus isolates from Alexandria Main University Hospital. Supplemented with additional publicly available genomes from the region (34 S. aureus and 6 S. haemolyticus), we present the largest genomic study of staphylococcal Middle Eastern isolates. These genomes include 20 S. aureus multilocus sequence typing (MLST) types and 9 S. haemolyticus MLSTs, including 3 and 1 new MLSTs, respectively. Phylogenomic analyses of each species core genome largely mirrored MLSTs, irrespective of geographical origin. The hospital-acquired spa t037/SCCmec III/MLST CC8 clone represented the largest clade, comprising 22% of S. aureus isolates. Similar to other regional genome surveys of S. aureus, the Middle Eastern isolates have an open pangenome, a strong indicator of gene exchange of virulence factors and antibiotic resistance genes with other reservoirs. We recommend stricter implementation of antibiotic stewardship and infection control plans in the region.


2021 ◽  
pp. 257-267
Author(s):  
Wafaa A. Abd El-Ghany

Staphylococcus aureus is a Gram-positive coccus normally present on the skin and internal organs of animals, birds, and humans. Under certain conditions, S. aureus could produce septicemia and affection of the skin, joints, and heart, as well as sepsis and death. The pathogenicity of S. aureus is associated with the presence of some virulent surface proteins and the production of some virulent toxins and enzymes. This pathogen is considered one of the most important and worldwide foodborne causes as it is incriminated in most cases of food poisoning. The hazardous use of antibiotics in the veterinary field leads to the development of multidrug-resistant S. aureus strains that can be transmitted to humans. The incidence of methicillin-resistant S. aureus (MRSA) strains has increased globally. These resistant strains have been detected in live animals, poultry, and humans. In addition, retail animal products, especially those of avian origin, are considered the main source of MRSA strains that can be easily transmitted to humans. MRSA infection is regarded as nosocomial or occupational. Humans get infected with MRSA strains through improper handling or preparation of contaminated animals or poultry carcasses or improper cooking with contaminated meat. Live birds also can transmit MRSA to close-contact workers in poultry farms. Transmission of MRSA infection in hospitals is from an infected individual to a healthy one. Prevention and control of MRSA are based on the application of hygienic measures in farms as well as proper processing, handling, and cooking of retail poultry products. The cooperation between veterinary and human practitioners is a must to avoid the possibility of zoonotic transmission. Accordingly, this review focused on the sources and transmission of MRSA infection, virulence and resistance factors, incidence and prevalence in poultry and different products, antibiotic resistance, and prevention and control strategies.


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.


2021 ◽  
Vol 2 (4) ◽  
pp. 26-35
Author(s):  
Muhammad Ramzan ◽  

Basic soil composition, or more precisely, soil organic matter, soil clay mineralogy and soil texture have been in the core of most infrared spectroscopy research for soils. Of course, nutrient availability, soil structure, soil microbial activity and soil fertility have also been a major subject of interest over the past two decades. The determination of soil nutrients is now becoming a routine work at large scale to gain high yield. The large number of soil nutrients determining techniques are used. The current paper presented that among tested techniques, Near-infrared reflectance spectroscopy (NIRS) is a best technique which has been used widely with minimum time, low in cost, ecofriendly and rapid determination of chemical, physical properties and organic matter present in soil. Obviously, this useful technique can be used to estimate properties such as mineral composition, SOM, water, percentage of carbon, nitrogen and clay content. It could be used directly in soil mapping, for monitoring soil, for making inferences about its quality and function, and making geomorphological interpretations of its distribution. The development of most accurate and trustworthy NIRS approaches are required.


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