Molecular analysis and the toxin, MSCRAMM, and biofilm genes of methicillin-resistant Staphylococcus aureus strains isolated from pemphigus wounds: A study based on SCCmec and dru typing

Investigation of SCCmec types using the real time PCR method in cefoxitin-resistant Staphylococcus aureus isolates

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen that can cause many community and hospital-acquired infections. This study was conducted to investigate the SCCmec gene types responsible for methicillin resistance in MRSA isolates isolated from hospitalised patients.

MATERIAL AND METHODS

MRSA isolates isolated from samples sent from various clinics to Gaziantep University Hospital Microbiology Laboratory between March 2021-January 2022 were included in the study. Bacteria were identified using by VITEK 2 automated system. Cefoxitin (FOX) resistance was determined by the disc diffusion method according to EUCAST standards. Cefoxitin resistance was confirmed by the Penicillin Binding Protein 2' latex agglutination test. Types of mecA, mecC, coa, nuc, Panton Valentin Leukocidin (PVL), ccrC2, class A mec, SCCmec types in isolates detected as MRSA were investigated by real-time PCR.

RESULTS

In this study, 116 isolates meeting the study criteria were examined. By detecting the nuc and coa genes in all isolates by PCR, the phenotypic identification of S.aureus was confirmed. While the mecA gene was detected in all MRSA isolates, no mecC gene was detected in any isolates. Detected SCCmec types were as follows; SCCmec Type 1 (2.6%), Type II (28.4%), Type III (12.9%), Type IVa (11.2%), Type IVb (3.4%), Type IVc (3.4%), Type IVg (12.1%), Type V (0.9%), Type VII (4.3%), Type VIII (18.1%), Type IX (0.9%), Type XII (1.7%). On the other hand, SCCmec Type VI, X, XI and XIII were not found in any isolate. It was determined that four of the MRSA isolates (3.4%) carried the PVL gene that two (50%) of these were found in SCCmec Type VIII.

CONCLUSION

Monitoring of FOX resistance is an effective and safe method for determination of MRSA isolates. The change in the mec gene causes resistance, which should be monitored regularly with molecular methods. Our study is the first study in Turkey.

Profile of Cutaneous Bacterial Flora in Pemphigus Patients

Objectives  Pemphigus, a group of autoimmune bullous diseases, can be fatal, resulting from overwhelming opportunistic infection of lesions secondary to cutaneous bacterial infections. This study aimed to look into the cutaneous bacterial infection profile of pemphigus patients as timely identification and appropriate treatment can play a major role in reducing mortality. Materials and Methods  Pus samples/swabs received from patients with pemphigus over a 2-year period from July 2018 to June 2020 were subjected to standard microbiological culture techniques and susceptibility testing. The frequency of isolation and susceptibility profile of the different bacterial pathogens toward various antimicrobial agents were interpreted and analyzed as per the Clinical and Laboratory Standards Institute's guidelines. Results  Samples from 315 patients were received during the study period comprising of 203 (64.4%) males and 112 (35.5%) females. Of 211 samples which were culture-positive, a total of 245 bacterial isolates were obtained, comprising of 158 Gram-positive cocci and 87 Gram-negative bacilli. Staphylococcus aureus (138, 56.3%) was the most common isolate followed by Pseudomonas aeruginosa (41, 16.7%) and Escherichia coli (16, 6.5%). Methicillin resistance was observed in 24.6% Staphylococcus aureus isolates and carbapenem resistance in 9.5 to 14.6% Gram-negative bacilli. Conclusions  Study findings emphasize the need for continuous monitoring of cutaneous pemphigus lesions for appropriate choice of antimicrobial therapy.

Genetic Diversity, Antimicrobial Resistance, and Virulence Factors of Enterococcus Faecalis Isolates Obtained from Stool Samples of Hospitalized Patients

Background: Enterococcus faecalis rapidly develops resistance to different antibiotics, thereby resulting in serious nosocomial infections associated with high mortality rates and different problems in the healthcare systems. Objectives: This study aimed to analyze the genetic diversity, antimicrobial resistance, and virulence factors of E. faecalis isolates obtained from the stool samples of patients in a hospital in the center of Iran. Methods: In this cross-sectional descriptive-analytical study, 108 stool samples were collected from September 2019 to February 2020 from 108 patients hospitalized in a hospital in the center of Iran. Enterococcus faecalis isolates were detected using the ddlE gene detection technique, and antimicrobial resistance testing was performed using the disc agar diffusion method. Moreover, polymerase chain reaction (PCR) was used to detect antimicrobial resistance genes and virulence factors. Genetic diversity was also analyzed by enterobacterial repetitive intergenic consensus using PCR (ERIC-PCR). The BioNumerics software was used to construct a dendrogram. Results: Of 108 isolates, 50 samples were E. faecalis (46.2%). The prevalence of multidrug resistance among E. faecalis isolates was 62%, and most isolates were resistant to antibiotics tetracycline (70%), erythromycin (68%), and rifampin (60%). Among the E. faecalis isolates, the most prevalent antimicrobial resistance genes were ermB (96%), aph (2′′) Ia (66%), aac(6′)-Ie (40%), and ermC (30%), and the most prevalent virulence genes were gelE (78%), asa1 (74%), and esp (74%). The genetic diversity analysis showed 25 ERIC types in two major clusters (ie, clusters H and J) and eight minor clusters (ie, clusters A-G and I). There was no significant difference between clusters H and J in terms of antimicrobial resistance and resistance genes (P > 0.05). In contrast, the prevalence of the asa1 gene was significantly higher in cluster J than in cluster H (P < 0.05). Conclusions: This study showed the high prevalence of multidrug resistance, and high heterogeneity among the E. faecalis isolates obtained from the stool samples of hospitalized patients.

Genetic Diversity, Antimicrobial Resistance Pattern, and Biofilm Formation in Klebsiella pneumoniae Isolated from Patients with Coronavirus Disease 2019 (COVID-19) and Ventilator-Associated Pneumonia

Introduction

Patients with acute respiratory distress syndrome caused by coronavirus disease 2019 (COVID-19) are at risk for superadded infections, especially infections caused by multidrug resistant (MDR) pathogens. Before the COVID-19 pandemic, the prevalence of MDR infections, including infections caused by MDR Klebsiella pneumoniae (K. pneumoniae), was very high in Iran. This study is aimed at assessing the genetic diversity, antimicrobial resistance pattern, and biofilm formation in K. pneumoniae isolates obtained from patients with COVID-19 and ventilator-associated pneumonia (VAP) hospitalized in an intensive care unit (ICU) in Iran.

Methods

In this cross-sectional study, seventy K. pneumoniae isolates were obtained from seventy patients with COVID-19 hospitalized in the ICU of Shahid Beheshti hospital, Kashan, Iran, from May to September, 2020. K. pneumoniae was detected through the ureD gene. Antimicrobial susceptibility testing was done using the Kirby-Bauer disc diffusion method, and biofilm was detected using the microtiter plate assay method. Genetic diversity was also analyzed through polymerase chain reaction based on enterobacterial repetitive intergenic consensus (ERIC-PCR). The BioNumerics software (v. 8.0, Applied Maths, Belgium) was used for analyzing the data and drawing dendrogram and minimum spanning tree. Findings. K. pneumoniae isolates had varying levels of resistance to antibiotics meropenem (80.4%), cefepime-aztreonam-piperacillin/tazobactam (70%), tobramycin (61.4%), ciprofloxacin (57.7%), gentamicin (55.7%), and imipenem (50%). Around 77.14% of isolates were MDR, and 42.8% of them formed biofilm. Genetic diversity analysis revealed 28 genotypes (E1-E28) and 74.28% of isolates were grouped into ten clusters (i.e., clusters A-J). Clusters were further categorized into three major clusters, i.e., clusters E, H, and J. Antimicrobial resistance to meropenem, tobramycin, gentamicin, and ciprofloxacin in cluster J was significantly higher than cluster H, denoting significant relationship between ERIC clusters and antimicrobial resistance. However, there was no significant difference among major clusters E, H, and J respecting biofilm formation.

Conclusion

K. pneumoniae isolates obtained from patients with COVID-19 have high antimicrobial resistance, and 44.2% of them have genetic similarity and can be clustered in three major clusters. There is a significant difference among clusters respecting antimicrobial resistance.