Antibacterial effects of vancomycin in combination with methicillin against methicillin-resistant and methicillinsensitive Staphylococcus aureus

Background and aims: Staphylococcus aureus is considered as a frequent cause of infections. Therefore, antibacterial agents including β-lactam are normally used to treat these infections while the emergence of antibiotic resistance is one of the major clinical problems in this respect. Accordingly, combination antibacterial therapy is one way to alleviate this problem. As a result, the present study aimed to investigate the combined effects of vancomycin and methicillin on clinical isolates of methicillin-resistant S. aureus (MRSA) and methicillinsensitive S. aureus (MSSA). In addition, a series of follow-up studies were performed to evaluate the antibacterial activity. Methods: The current cross-sectional study was conducted on 40 hospitalized patients from various clinical samples such as pus/wound swabs, blood, urine and sputum during a 6-month period in 2017. To this end, the antibacterial activities of vancomycin and methicillin, alone and in combination were investigated against MRSA and MSSA. Eventually, the inhibitory effects of vancomycin and methicillin alone and in combination were studied on the growth profile of MRSA and MSSA, as well as the expression of mecA gene. Results: Based on the results, the significant synergistic and partial synergistic activity with fractional inhibitory concentration (FIC) and fractional bactericidal concentration (FBC) indexes ranged from 0.27-0.938 and 0.313-0.844, respectively, in the combination of vancomycin and methicillin in MRSA and MSSA isolates. Further, the obtained data indicated that the combination of vancomycin and methicillin had a synergistic effect against MRSA isolates (P<0.01). The expression levels of the mecA gene were down-regulated by 5.25- fold in the combination of vancomycin and methicillin in MRSA isolate (P<0.001). Conclusion: In general, these events may reflect the potential uses of vancomycin and methicillin combination against MRSA. However, a greater understanding of the underlying molecular mechanisms of vancomycin and methicillin in combination could contribute to the development of therapeutic strategies.

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Toxin production and drug resistance profiles of pediatric methicillin-resistant Staphylococcus aureus isolates in Tehran

The Journal of Infection in Developing Countries ◽

10.3855/jidc.9360 ◽

2017 ◽

Vol 11 (10) ◽

pp. 759-765 ◽

Cited By ~ 3

Author(s):

Mozhgan Esmaeili Benvidi ◽

Hamidreza Houri ◽

Zohreh Ghalavand ◽

Bahram Nikmanesh ◽

Hadi Azimi ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Methicillin Resistant Staphylococcus Aureus ◽

Meca Gene ◽

Toxin Production ◽

Cross Sectional Study ◽

Biochemical Tests ◽

Cross Sectional ◽

Methicillin Resistant ◽

Present Cross Sectional Study ◽

Invasive Diseases

Introduction: Staphylococcus aureus is known to be a major cause of skin and soft tissue infections, pneumonia and invasive diseases. In this study, attempts were made to examine the prevalence of tsst-1, eta, etb, and luk-PV genes among methicillin-resistant S. aureus (MRSA) isolated from children in Tehran. Methodology: In the present cross-sectional study, a total of 100 MRSA were isolated from children who were referred to a pediatric hospital during 11-month period of September 2014 to August 2015. Isolates were identified using biochemical tests and then, using PCR, the isolates were tested for the presence of mecA, tsst-1, eta, etb, and luk-PV genes. Susceptibility of isolates to cefoxitin, penicillin, erythromycin, clindamycin, gentamicin, rifampin, minocycline, co-trimoxazole, linezolid, and vancomycin were evaluated using standard methods. Results: It was found that the MRSA isolates had the greatest resistance to clindamycin (72%) and erythromycin (59%), while the lowest rates of resistance were observed to be related to minocycline (6%) and rifampin (12%). All of isolates were sensitive to vancomycin and linezolid. The mecA gene was detected in all the isolates. Moreover, luk-PV and tsst-1 were detected in 18% and 17% of the isolates, respectively. None of the isolates harbored eta and etb genes. Conclusions: Our data provide specifications about the toxin production status of S. aureus isolates from pediatric children. The current study showed increased resistance to different antibiotics in S. aureus isolates. Therefore, to prevent multi-resistance to other antibiotic classes, it is essential to withhold prescriptions and stop unessential use of available antibiotics.

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Colonization and Antibiotic Resistance Profiling of Methicillin Resistant Staphylococcus Aureus (Mrsa) in Patients from Tertiary

THE JOURNAL OF MICROBIOLOGY AND MOLECULAR GENETICS ◽

10.52700/jmmg.v1i3.11 ◽

2020 ◽

Vol 1 (3) ◽

pp. 31-39

Author(s):

Madiha Khan ◽

Wafa Komal ◽

Mushtaq A. Saleem ◽

Naveed Ahmad ◽

Zara Rafaque ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Methicillin Resistant Staphylococcus Aureus ◽

Culture Media ◽

Tertiary Care ◽

Age Groups ◽

Cross Sectional Study ◽

Clinical Samples ◽

Care Hospital ◽

Cross Sectional ◽

Methicillin Resistant

The methicillin resistant Staphylococcus aureus (MRSA) is affecting the economy worldwide contributing to the increased morbidity and treatment costs. The present cross sectional study was conducted to determine the association of MRSA with kidney and liver patients from Tertiary Care Hospital in Lahore, Pakistan and its antibacterialresistance patterns. The study was conducted for the period of one year; from April 2019 to April 2020. A total of 1984 different samples were obtained and examined for bacterial cultures using standard procedures. From total samples, 51.05% were collected from male and the rest 48.95% were collected from females including different age groups. Samples were inoculated on different culture media for isolation of S. aureus and susceptibility testing. A total of 253/1984 clinical samples exhibited S. aureus characteristics while 39 of 253 S. aureus (15.41%) were identified as MRSA. MRSA strains were found highly resistant to Amikacin (AK), Cefoxitin (FOX),Clindamycin (DA), Fusidic acid (FD), Gentamicin (CN) and Tobramycin (TOB) while highest sensitivity was noted against Vancomycin (100%) and Linezolid (100%). The presence of MRSA and multidrug resistance pose serious therapeutic burden to critically ill patients. A systematic and concerted effort is essential to identify high-risk patients rapidly and to reduce the burden of antimicrobial resistance.

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Panton Valentine Gene in both Community-acquired and Healthcare-acquired Methicillin Resistant Staphylococcus aureus Isolates from Ain Shams University Hospitals

QJM ◽

10.1093/qjmed/hcaa053 ◽

2020 ◽

Vol 113 (Supplement_1) ◽

Author(s):

R A Mohamed ◽

L F Fathi ◽

N N Salaheldeen

Keyword(s):

Staphylococcus Aureus ◽

Methicillin Resistant Staphylococcus Aureus ◽

Methicillin Resistance ◽

Meca Gene ◽

Cross Sectional Study ◽

P Value ◽

University Hospitals ◽

Cross Sectional ◽

Mannitol Salt Agar ◽

Methicillin Resistant

Abstract Background Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen that is associated with both hospital and community infections. Panton Valentine leukocidin (PVL) is an important virulence factor of S. aureus that is considered by many authors a marker of community acquired MRSA (CA-MRSA). Aim of the Work This study aimed to determine the prevalence of PVL genes among healthcare acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) and CA-MRSA isolates, and to test the hypothesis that PVL is a reliable marker of CA-MRSA isolates. Material and Methods This comparative cross-sectional study was done on fifteen community acquired methicillin resistant Staphylococcus aureus (CA-MRSA) and fifteen hospital acquired methicillin resistant Staphylococcus aureus (HA-MRSA), obtained from patients attending outpatient clinics, presenting with community-acquired pyogenic infections and patients with healthcare acquired pyogenic infections in Intensive Care Units (ICUs), during the period from May 2017 till February 2018. Clinical specimens included pus and different body fluids. Staphylococcus aureus was isolated and identified using conventional microbiological methods3. Isolates were then tested for methicillin resistance by culture on mannitol salt agar (MSA) with cefoxitin4. The presence of mecA and pvl genes in all MRSA isolates was subsequently detected by PCR5,6. Results Among 15 HA-MRSA isolates, mecA gene was positive in 40% (6/15) of isolates, while pvl gene was positive in 53.3% (8/15) of isolates. Among 15 CA-MRSA isolates, mecA gene was positive in 46.7% (7/15) of isolates, while pvl gene was positive in 26.7% (4/15) of isolates. Conclusion We conclude that pvl gene is not a sole genetic marker for diagnosis CA-MRSA, as there was no significant correlation between mecA that encodes for methicillin resistance and pvl genes among fifteen CA-MRSA isolates (P value =1).

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The Prevalence of antimicrobial resistance in Staphylococcus aureus and coagulase-negative Staphylococci strains isolated from inpatients

10.21203/rs.3.rs-24115/v2 ◽

2020 ◽

Author(s):

Parva Farmehr ◽

Javad fathi ◽

Mahtab Hadadi ◽

mohammad motamedifar

Keyword(s):

Staphylococcus Aureus ◽

Antimicrobial Susceptibility ◽

Antibacterial Agents ◽

Cross Sectional Study ◽

Clinical Samples ◽

Coagulase Negative Staphylococci ◽

Cross Sectional ◽

Antibiotic Policy ◽

Methicillin Resistant ◽

Southwest Of Iran

Abstract Objectives: Globally nosocomial infection is a significant problem. Methicillin resistant Staphylococcus aureus (MRSA) and Methicillin resistant coagulase negative staphylococci (MRCoNS) are major causes of nosocomial infections. Aim of this study was to determine the prevalence and antimicrobial susceptibility of MRSA and MRCoNS in the southwest of Iran. This cross-sectional study was conducted on 221 non-duplicated staphylococci isolates collected from teaching hospital in Shiraz. The prevalence of MRSA and MRCoNS in clinical samples was identified with conventional microbiological tests. After identification, all of the isolates were subjected to antimicrobial susceptibility test and PCR to identify the presence of femA, mecA and pvl genes. Results: 70 (41.7 %) MRSA among 168 S. aureus, and 26 (15.48%) MRCoNS among 53 CoNS were examined. All of the isolates were susceptible to Trimethoprim/Sulfamethoxazole (100%). Chloramphenicol (65%) and Gentamicin (23%) were the other most active antibacterial agents against MRSA and MRCoNS. The frequency of pvl gene among S. aureus strains was 3.57%. There is need for developing the antibiotic policy and limiting the use of powerful antibiotics.

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Prevalence of Staphylococcus aureus Isolated from Clinical Samples in a Tertiary Care Hospital: A Descriptive Cross-sectional Study

Journal of Nepal Medical Association ◽

10.31729/jnma.4673 ◽

2019 ◽

Vol 57 (220) ◽

Author(s):

Jyotshna Sapkota ◽

Manisha Sharma ◽

Beena Jha ◽

Chandra Prakash Bhatt

Keyword(s):

Staphylococcus Aureus ◽

Confidence Interval ◽

Methicillin Resistant Staphylococcus Aureus ◽

Cross Sectional Study ◽

Aureus Strain ◽

Clinical Samples ◽

Wound Infections ◽

Sectional Study ◽

Cross Sectional ◽

Methicillin Resistant

Introduction: Staphylococcus aureus is one of the commonest cause of nosocomial infections. Resistant Staphylococcus aureus strain has become a matter of concern. This study was done to find out the prevalence of Staphylococcus aureus from different clinical samples. Methods: The descriptive cross-sectional study was carried out in the Clinical Microbiology laboratory from January 2019 to June 2019. Ethical approval was received from the Institutional Review Committee (Ref: 28122018010). Six hundred sixty-six sample size was calculated. Convenient sampling was done. Staphylococcus aureus was identified on the basis of its microscopy and morphological characteristics followed by catalase and coagulase test. Antibiotic sensitivity test of misolated pathogens was done using Muller Hinton Agar by Kirby-Bauer method. Statistical analysis was done by Excel 2018, point estimate at 95% confidence interval was calculated along with frequency and proportion for binary data. Results: Out of the 666 bacteria isolated from clinical specimens, 133 (19.96%) were Staphylococcus aureus at 95% confidence interval (129.91-136.01%). Seventy nine (78.95%) of which is isolated from pus and wound infections. Out of 133 Staphylococcus aureus, 70.64% were Methicillin-Resistant Staphylococcus aureus. Conclusions: This study provides valuable information regarding the high prevalence of Staphylococcus aureus from pus and wound infections. The alarming number of Methicillin-Resistant Staphylococcus aureus is worrisome finding. Antibiotics like Vancomycin and Linezolid which has not developed resistance should be cautiously used only in Methicillin-Resistant Staphylococcus aureus cases.

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Mutation-Based Antibiotic Resistance Mechanism in Methicillin-Resistant Staphylococcus aureus Clinical Isolates

Pharmaceuticals ◽

10.3390/ph14050420 ◽

2021 ◽

Vol 14 (5) ◽

pp. 420

Author(s):

Tanveer Ali ◽

Abdul Basit ◽

Asad Mustafa Karim ◽

Jung-Hun Lee ◽

Jeong-Ho Jeon ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Antibiotic Resistance ◽

Active Site ◽

Methicillin Resistant Staphylococcus Aureus ◽

Meca Gene ◽

Resistance Mechanism ◽

Ligand Docking ◽

Clinical Samples ◽

Allosteric Site ◽

Methicillin Resistant

β-Lactam antibiotics target penicillin-binding proteins and inhibit the synthesis of peptidoglycan, a crucial step in cell wall biosynthesis. Staphylococcus aureus acquires resistance against β-lactam antibiotics by producing a penicillin-binding protein 2a (PBP2a), encoded by the mecA gene. PBP2a participates in peptidoglycan biosynthesis and exhibits a poor affinity towards β-lactam antibiotics. The current study was performed to determine the diversity and the role of missense mutations of PBP2a in the antibiotic resistance mechanism. The methicillin-resistant Staphylococcus aureus (MRSA) isolates from clinical samples were identified using phenotypic and genotypic techniques. The highest frequency (60%, 18 out of 30) of MRSA was observed in wound specimens. Sequence variation analysis of the mecA gene showed four amino acid substitutions (i.e., E239K, E239R, G246E, and E447K). The E239R mutation was found to be novel. The protein-ligand docking results showed that the E239R mutation in the allosteric site of PBP2a induces conformational changes in the active site and, thus, hinders its interaction with cefoxitin. Therefore, the present report indicates that mutation in the allosteric site of PBP2a provides a more closed active site conformation than wide-type PBP2a and then causes the high-level resistance to cefoxitin.

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Detection of mecA gene by latex agglutination and its molecular analysis by PCR in methicillin resistant staphylococcus aureus.

The Professional Medical Journal ◽

10.29309/tpmj/2020.27.07.3752 ◽

2020 ◽

Vol 27 (07) ◽

pp. 1363-1370

Author(s):

Aneela Khawaja ◽

Iffat Javed ◽

Sohaila Mushtaq ◽

Saeed Anwar ◽

Faiqa Arshad ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Methicillin Resistant Staphylococcus Aureus ◽

Methicillin Resistance ◽

Meca Gene ◽

Latex Agglutination ◽

Medical Institute ◽

Cross Sectional ◽

Methicillin Resistant ◽

Agglutination Method ◽

Resistant Strains

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.

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Antibiotic resistance pattern of Staphylococcus aureus with reference to MRSA isolates from pediatric patients

10.21203/rs.2.10785/v1 ◽

2019 ◽

Author(s):

Raja Ram Gurung ◽

Prashanna Maharjan ◽

Ganga GC

Keyword(s):

Staphylococcus Aureus ◽

Antibiotic Resistance ◽

Pediatric Patients ◽

Methicillin Resistant Staphylococcus Aureus ◽

Current Status ◽

Clinical Samples ◽

Resistance Pattern ◽

Isolation And Identification ◽

Cross Sectional ◽

Methicillin Resistant

Abstract Background: Staphylococcus aureus is one of the important superbugs distributed throughout the world. It causes minor skin infections to severe complications including nosocomial infections in both hospitals and community settings. These strains have multi-drug resistant property. Hence, they are difficult to manage which increase health-related costs and simultaneously intensifying the need for new antibiotics. The extent of Methicillin-Resistant Staphylococcus aureus (MRSA) in children is largely unknown. The study determines the current status of S. aureus and MRSA causing various infections in pediatric patients visiting International Friendship Children’s Hospital (IFCH). Methods: A cross-sectional study was conducted among patients visiting a hospital. Various clinical specimens were aseptically collected and processed according to standard microbiological procedures. Isolation and identification of S. aureus were done by microscopy, mannitol fermentation, and coagulase positivity. All identified S. aureus isolates subjected to in-vitro antibiogram by Kirby-Bauer disc diffusion technique adopting Clinical and Laboratory Standards Institute (CLSI) guideline. Isolates resistant to cefoxitin were considered to be MRSA. Whereas, isolates produced D-shaped inhibition zone around clindamycin when kept near erythromycin were considered to be Inducible Clindamycin Resistant (ICR). Results: 672 various types of clinical samples were processed from the microbiology laboratory from June and November 2015. Out of 300 culture positive samples, 52 (17.3%) were S. aureus isolates, among them 39 (75.0%) were found to be MRSA. The D-test showed that Macrolide-Lincosamide-Streptogramin-B (MLSB) phenotype was 15.4%. Conclusion: The study shows the MRSA occurrence is prevalent in pediatric patients and newer classes’ drugs are found more effective than β-lactam drugs to treat S. aureus infection. However, restriction on the indiscriminate use of such drugs may be an effective strategy to control the drug resistance. Keywords: Methicillin-Resistant Staphylococcus aureus (MRSA), Macrolide-Lincosamide-Streptogramin B (MLSB) phenotype, Inducible Clindamycin Resistant (ICR) test or D-zone test, Antibiotic resistance, Nepal

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