Antibiotic Resistance Patterns and Virulence Determinants of Different SCCmec and Pulsotypes of Staphylococcus Aureus Isolated from a Major Hospital in Ilam, Iran

Spectrum of Virulence Factors in Clinical Isolates of Staphylococcus aureus and Prevalence of SCCmec Types in Methicillin-Resistant Staphylococcus aureus in a Tertiary Care Center

Background  Methicillin-resistant Staphylococcus aureus (MRSA) is a widely recognized multidrug-resistant bacteria presenting a major therapeutic challenge to clinicians. Staphylococcus aureus possesses a number of pathogenicity factors that attribute to the severity of infections. This study was undertaken to investigate the common virulence genes in clinical isolates of Staphylococcus aureus , determine their antimicrobial susceptibility profile, and to characterize the staphylococcal cassette chromosome mec (SCCmec) types among MRSA in a tertiary care center. Materials and Methods  A total of 133 clinical isolates were included in this study. Susceptibility to various antibiotics was determined by disc diffusion method. Methicillin resistance was screened using cefoxitin disc; m ecA and mecC genes were detected using polymerase chain reaction (PCR). PCR was done to detect 12 virulence factors such as hla , hlb , fnbA , fnbB , sea , seb , sec , icaA , clfA , tst , pvl, and eta . SCCmec typing was done by multiplex PCR. Results  Of the 133 clinical isolates, 54 (40.6%) were MRSA. The most common virulence gene detected was hlb (61.6%), hla (39%), and fnbA (37%). SCCmec type I was the most predominant. Mortality rate of 6.7% was observed among patients with staphylococcal infections. Univariate analysis of mortality associated virulence genes did not reveal any significant association between virulence genes and mortality. Conclusion  The distribution of virulence genes is similar in both MRSA and methicillin-sensitive Staphylococcus aureus . MRSA belongs to the SCCmec types I to IV. Possession of multiple virulence factors and multidrug resistance profile makes Staphylococcus aureus a formidable pathogen in clinical settings.

Indoor Air Quality in Healthcare Units—A Systematic Literature Review Focusing Recent Research

The adequate assessment and management of indoor air quality in healthcare facilities is of utmost importance for patient safety and occupational health purposes. This study aims to identify the recent trends of research on the topic through a systematic literature review following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) methodology. A total of 171 articles published in the period 2015–2020 were selected and analyzed. Results show that there is a worldwide growing research interest in this subject, dispersed in a wide variety of scientific journals. A textometric analysis using the IRaMuTeQ software revealed four clusters of topics in the sampled articles: physicochemical pollutants, design and management of infrastructures, environmental control measures, and microbiological contamination. The studies focus mainly on hospital facilities, but there is also research interest in primary care centers and dental clinics. The majority of the analyzed articles (85%) report experimental data, with the most frequently measured parameters being related to environmental quality (temperature and relative humidity), microbiological load, CO2 and particulate matter. Non-compliance with the WHO guidelines for indoor air quality is frequently reported. This study provides an overview of the recent literature on this topic, identifying promising lines of research to improve indoor air quality in healthcare facilities.

Emergence of Methicillin-Resistant Staphylococcus aureus ST239/241 SCCmec-III Mercury in Eastern Algeria

In this paper, we investigate the epidemiology of infections-associated Staphylococcusaureus (S. aureus) from the Medical Intensive Care Unit (MICU) at University Hospital Center of Constantine (UHCC) in Algeria, with a special emphasis on methicillin-resistant strains (MRSA) revealed by cefoxitin disks (30 μg), then confirmed by penicillin-binding protein (PBP2a) agglutination and real-time polymerase chain reaction (RT-PCR) targeting mecA and mecC genes. Staphylococcal Cassette Chromosome mec (SCCmec type), staphylococcal protein A (spa-type), multilocus sequence type (MLST), Panton-Valentine Leucocidin (PVL), and toxic shock syndrome toxin-1 (TSST-1) were further investigated in all isolates, and whole genome sequencing was performed for a selected subset of three hospital-acquired MRSA (HA-MRSA) isolates. A measurement of 80% out of the 50 S. aureus isolates were identified as HA-MRSA harbouring the mecA gene, and 72.5% of them were multidrug resistant (MDR). Twelve STs, four different SCCmec cassettes, fourteen spa types, ten isolates Panton-Valentine Leukocidin (PVL)-positive, and three isolates TSST-1 were identified. Interestingly, there was a high prevalence (n = 29; 72.5%) of a worrisome emerging clone: the HA-MRSA ST239/241 SCCmec-III mercury with PVL negative, resistant to β-lactams, aminoglycosides, quinolones, and tetracyclines. Other clones of HA-MRSA isolates were also identified, including PVL-positive ST80 SCCmec-IV/SCCmec-unknown (22.5%), ST34 SCCmec-V with TSST-1 positive (2.5%), and PVL-negative ST72 SCCmec-II (2.5%). Genome analysis enables us to describe the first detection of both PVL-negative HA-MRSA ST239/241 SCCmec-III mercury carrying ccrC, as well as SCCmec-V cassette, which dramatically changes the epidemiology of S. aureus infections in one of the hospitals in eastern Algeria.

Relationship between MLSB resistance and the prevalent virulence genotypes among Bulgarian Staphylococcus aureus isolates

The aim of this study was to investigate the rate of resistance to macrolide-lincosamide-streptogramin B (MLSB) antibiotics, the mechanisms underlying this resistance and to evaluate their relationship with virulence genes profiles of 435 Bulgarian clinical isolates Staphylococcus aureus. The highest resistance was observed to penicillin (96.09%), followed by resistance to erythromycin and clindamycin (34.02 and 22.76%, respectively). Of the tested clinical strains of S. aureus, 96.09% contained the blaZ gene associated with penicillin resistance and 11.03%, the mecA gene responsible for methicillin resistance. The most prevalent were the erm genotypes associated with the presence mainly of ermA and ermC genes followed by ermB. The frequency rates of these genes, alone or in combinations were ermA 41.89%, ermB 27.70%, ermC 43.99%. The majority of Bulgarian macrolide resistant S. aureus exhibited cMLS phenotype, in 58.78% (P = 0.0036). The following virulence genotypes were present significantly more often in the macrolide resistant S. aureus isolates among the studied ones: hlg; hlg,seb; hlg,seb,sec; hlg,seb,seh; hlg,sec; hlg,sec,sei; hlg,sec,sei; hlg,sei; hlg,sei,sej; hlg,sej. This survey found correlation between the virulence profiles with a small number of genes and macrolide resistance among Bulgarian clinical S. aureus isolates, in contrast to sensitive strains, which possessed profiles predominantly with multiple genes.

An array of multiplex PCR assays for detection of staphylococcal chromosomal cassette mec (SCCmec) types among staphylococcal isolates

Staphylococcal Cassette Chromosome mec (SCCmec) element plays a key role in development of resistance by carrying different resistance factors. Therefore, routine and rapid diagnostic approach is considered advantageous for the easy detection of SCCmec elements. So, here we have described the use of three sets of multiplex PCR assay, which can be used to identify SCCmec type I to type XII, unlike other known protocols. MRSA isolates of both hospital and community settings had been utilized to confirm the sensitivity of the method. All the isolates were examined for SCCmec types using multiplex PCR assay followed by sequencing of amplified products. The results confirmed the detection of SCCmec type I, type II, type III, type IV, type V, type VI, type VII, type VIII and type XII, where SCCmec type II having ST1551 and type V with ST2416 were found to be associated with multidrug resistance and were highly prevalent in the study area. This method will be useful for epidemiological assessment as it will be easier to track the resistance among staphylococci for control of infections and its management.