Molecular analysis of accessory gene regulator functionality and virulence genes in Staphylococcus aureus derived from pediatric wound infections

Maleki, Donya; Ghalavand, Zohreh; Laabei, Maisem; Nikmanesh, Bahram; Houri, Hamidreza; Kodori, Mansoor; Hashemi, Ali; Kadkhoda, Hiva; Eslami, Gita

doi:10.1016/j.meegid.2019.05.013

Cited by 12 publications

(10 citation statements)

References 37 publications

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“…[15][16][17] Children are usually considered as the most vulnerable group to bacterial infections. 12,18 According to the global action plan on AMR endorsed by WHO, it is important to raise awareness on AMR through monitoring and research programs in different parts of the world. [19][20][21] AMR monitoring is critical and has several benefits including: 1) providing data on bacterial resistance rate, 2) helping select appropriate antibiotics and subsequently reduce AMR rate, 22 3) reduction in hospitalization rate and treatment costs, and 4) decrease in death rate.…”

Section: Introductionmentioning

confidence: 99%

<p>Evaluating the antimicrobial resistance patterns among major bacterial pathogens isolated from clinical specimens taken from patients in Mofid Children’s Hospital, Tehran, Iran: 2013–2018</p>

Azimi

Maham

Fallah

et al. 2019

IDR

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Background: This study evaluates the epidemiology and antimicrobial resistance profile of Gram-negative bacteria (GNB) and Gram-positive bacteria (GPB) isolated from clinical specimens in children admitted to Mofid Children's Hospital. Methods: This was a retrospective study of the patients' clinical specimens collected from January 2013 until the end of December 2018. All specimens were evaluated to determine the presence of infection-causing agents using a BACTEC 9120 blood culture. Isolation and identification of bacterial strains were performed using conventional biochemical tests. Antibiotic resistance was determined using Kirby-Bauer disk diffusion and broth microdilution methods. Results were interpreted according to CLSI and EUCAST. Results: A total of 1130 different pathogenic bacteria were detected from 14,690 different clinical specimens and the overall detection rate was 7.7% (1130/14,690). Among bacterial pathogen isolated from clinical specimens, 55% (n=622) were GNB and 45% (n=508) were GPB. The predominant GNB isolates were Pseudomonas aeruginosa, Klebsiella spp., Acinetobacter baumannii, Escherichia coli, Enterobacter spp., Citrobacter spp., respectively. Among GPB, CoNS was the most frequent and Enterococcus spp. was found to have low levels of resistance to linezolid. In GNB, most A. baumannii and P. aeruginosa were ceftriaxone resistant. P. aeruginosa was found to have low levels of resistance to levofloxacin and ciprofloxacin. Conclusions: Our findings revealed that the resistance rate among GNB and GPB associated with different infections in children is very high. These results suggest a constant screening and follow-up programs for the detection of antibiotic resistance, and it also suggests to develop antimicrobial stewardship programs in Tehran, Iran.

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Section: Introductionmentioning

confidence: 99%

<p>Evaluating the antimicrobial resistance patterns among major bacterial pathogens isolated from clinical specimens taken from patients in Mofid Children’s Hospital, Tehran, Iran: 2013–2018</p>

Azimi

Maham

Fallah

et al. 2019

IDR

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“…Similarly to our findings, in a collection of pediatric MSSA from SSTIs over a 43-month period in Athens, Greece, 93 % of isolates carried both eta and etb [ 14 ]. In a collection of S. aureus from SSTIs among pediatric patients referred to the Children’s Medical Center Hospital in Tehran, during one-year period (2017–2018), eta was the most prevalent gene with a high occurrence (100 % in both MRSA and MSSA) and etb was found in only 23.8 % of the MSSA population, whereas in our study etb was the predominant toxins’ gene in MSSA [ 24 ]. It is remarkable that almost all staphylococcal strains harbor both the eta and etb genes, in accordance with the study conducted in a single center (PAKCH) [ 14 ], whereas only 0.5 to 3 % of MSSA strains examined in previous studies carried those genes [ 25 ].…”

Section: Discussionmentioning

confidence: 75%

Emergence of a mupirocin-resistant, methicillin-susceptible Staphylococcus aureus clone associated with skin and soft tissue infections in Greece

et al. 2021

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Background Staphylococcus aureus causes various infections, including skin and soft tissue infections (SSTIs). In this study, methicillin-susceptible S. aureus (MSSA) from SSTIs among patients in three tertiary-care hospitals in Greece were studied in terms of antimicrobial resistance, clonal distribution, toxin and adhesin genes carriage. Results During a five-year period (2014–2018), 6145 S. aureus were recovered from 13,244 patients with SSTIs and tested for antimicrobial susceptibility. MSSA were 4806 (78.21 %) including 1484 isolates with mupirocin minimum inhibitory concentration (MIC) > 64 mg/L (30.88 %). Two hundred and sixty representative mupirocin-resistant MSSA were analyzed for genes encoding Panton-Valentine leukocidin (PVL, lukS/lukF-PV), exfoliative toxins (eta, etb), adhesin FnbA (fnbA) and resistance genes mupA (high-level resistance to mupirocin), fusB (fusidic acid), aminoglycosides’ modifying enzymes, ermA, ermC and msrA (macrolides/lincosamides) by PCRs. Strains were classified into clones by PFGE and MLST. All mupirocin-resistant MSSA were penicillin-resistant; 92.7 % expressed resistance to fusidic acid and 88.9 % to tobramycin. All 260 molecularly analyzed isolates were mupA-positive; all fusidic acid-resistant (241/260) carried fusB whereas, the tobramycin-resistant ones (230), ant(4′)-Ia. The majority carried eta (93.85 %), etb (98.08 %) and fnbA (88.85 %). PFGE typing revealed a mostly unvarying population; 260 MSSA were grouped into three types. One major eta/etb-positive clone comprising of 258/260 strains (99.2 %), PFGE type 1, was classified as ST121, including nine strains co-carrying PVL. Another PVL-positive strain was identified as ST1, and one toxins-negative as ST21. Conclusions A mupirocin-resistant MSSA clone, ST121, carrying resistance, exfoliative toxins and adhesin genes, was spread and predominated in SSTIs from patients in Greece during the five-year studied period.

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“…Genomic DNA was extracted using the High Pure PCR Template Preparation kit (Roche, Germany) consistent with the manufacturer’s instructions ( 13 ). Assessment of quantity and quality of each obtained DNA was examined using Nano-Drop (Thermo Fisher Scientific; USA).…”

Section: Methodsmentioning

confidence: 99%

Expression of type II toxin-antitoxin systems and ClpP protease of methicillin-resistant Staphylococcus aureus under thermal and oxidative stress conditions

Karimaei¹,

Kalani²,

Shahrokhi³

et al. 2021

IJM

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Background and Objectives: Staphylococcus aureus is a main human pathogen that causes a variety of chronic to persistent infections. Across the diverse factors of pathogenesis in bacteria, Toxin-Antitoxin (TA) systems can be considered as an antibacterial target due to their involvement in cellular physiology counting stress responses. Here, the expression of TA system genes and ClpP protease was investigated under the thermal and oxidative conditions in S. aureus strains. Materials and Methods: The colony-forming unit (CFU) was used to determine the effects of thermal and oxidative stresses on bacterial survival. Moreover, the expressions of TA system genes in S. aureus strains were evaluated 30 min and 1 h after thermal and oxidative stresses, respectively, by quantitative reverse transcriptase real-time PCR (qRT-PCR). Results: The cell viability was constant across thermal stress while oxidative stress induction showed a significantly decrease in the growth of Methicillin-Resistant S. aureus (MRSA) strain. Based on the qRT-PCR results, the expression of mazF gene increased under both thermal and oxidative stresses in the MRSA strain. Conclusion: A putative TA system (namely immA/irrA) most likely has a role under the stress condition of S. aureus. The MRSA strain responds to stress by shifting the expression level of TA genes that has diverse effects on the survival of the pathogen due to the stress conditions. The TA systems may be introduced as potential targets for antibacterial treatment.

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Molecular analysis of accessory gene regulator functionality and virulence genes in Staphylococcus aureus derived from pediatric wound infections

Cited by 12 publications

References 37 publications

<p>Evaluating the antimicrobial resistance patterns among major bacterial pathogens isolated from clinical specimens taken from patients in Mofid Children’s Hospital, Tehran, Iran: 2013–2018</p>

<p>Evaluating the antimicrobial resistance patterns among major bacterial pathogens isolated from clinical specimens taken from patients in Mofid Children’s Hospital, Tehran, Iran: 2013–2018</p>

Emergence of a mupirocin-resistant, methicillin-susceptible Staphylococcus aureus clone associated with skin and soft tissue infections in Greece

Expression of type II toxin-antitoxin systems and ClpP protease of methicillin-resistant Staphylococcus aureus under thermal and oxidative stress conditions

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