staphylococcus

Zinc oxide (ZnO) as an antimicrobial and non-toxic agent has been widely explored in comparison with other materials. The green manufacturing of mineral nanoparticles using plant extracts has outperformed other manufacturing methods due to many advantages.

ZnO nanoparticles (ZnO NPs) were synthesized using two distinct

chemical synthesis and a green method involving lemon leaf extract. The synthesized ZnO was characterized using UV-Vis, X-ray diffraction (XRD), scanning electron microscope (SEM) , and Fourier transform infrared spectroscopy (FTIR) analyses. The antibacterial activity of the resulting ZnO NPs was evaluated against two gram-negative bacterial strains, Escherichia coli and Pseudomonas aeruginosa, and one gram-positive strain, Staphylococcus aureus, using the etching diffusion method.

In this study, ZnO NPs were synthesized using a green method from an inexpensive and readily available source, lemon leaf extract, and compared with those synthesized by a chemical method. The results showed that ZnO NPs obtained via the green synthesis method had a semi-spherical shape with an average size of 14.25 nm, which is smaller than the average size of chemically synthesized ZnO NPs at 34 nm. The effectiveness of the ZnO NPs varied depending on the bacterial strain tested. Grampositive bacteria were more sensitive than gram-negative bacteria.

ZnO NPs produced from lemon leaf extract were most effective against S. aureus. Chemically synthesized ZnO NPs were more effective against gram-negative bacteria.

 Staphylococcus aureus ranks among the leading causes of serious nosocomial infections. One critical route for the spread of this bacterium within hospitals is via asymptomatic carriers, particularly healthcare providers. Staphylococcus aureus can exist as part of the normal skin flora and within the anterior nostrils of individuals, making healthcare providers a significant vector for transmission. Several genes associated with virulence, such as toxic shock syndrome toxin-1 (tsst-1), alpha-toxin (hla), and panton-valentine leucocidin (pvl), play pivotal roles in the pathogenicity and severity of infections caused by S. aureus.

 This study aimed to characterize S. aureus nasal carriage among healthcare providers in an intensive care unit (ICU), with a particular focus on antibiotic resistance profiles and the prevalence of virulence genes.

 Nasal swabs were collected from 120 healthcare workers in the ICU of Ganjavian hospital, Dezful, Iran. Standard microbiological procedures were employed for S. aureus detection. Antibiotic susceptibility testing was conducted using both disk diffusion and minimum inhibitory concentration methods. Polymerase chain reaction (PCR) was employed to identify the presence of the mecA gene and the virulence genes hla, tsst-1, and pvl. A statistical analysis was performed to evaluate the data.

 The study revealed that 12.5% of healthcare providers were carriers of S. aureus, with 26.6% of them harboring methicillin-resistant S. aureus (MRSA) strains. Antibiotic resistance patterns varied, with a notable resistance to erythromycin and penicillin. The hla gene was detected in 66.6% of S. aureus strains; nevertheless, the tsst-1 and pvl genes were not identified. The study suggests a potential association between high expression of the hla and mecA genes and antibiotic resistance.

 This study underscores the prevalence of S. aureus nasal carriage, antibiotic resistance patterns, and the distribution of virulence genes among healthcare providers in an ICU setting. The findings emphasize the significance of continuous surveillance and infection control strategies to mitigate the transmission of S. aureus and associated infections within healthcare facilities. The study recommends routine screening of ICU healthcare providers for asymptomatic S. aureus carriers and appropriate interventions to eliminate colonization.

Coagulase-negative staphylococci (CoNS) are rolled in severe infections in animals and nosocomial infections in humans. Given that staphylococci other than Staphylococcus aureus are often reported only as CoNS in medical diagnosis laboratories, this study aimed to determine the exact species of this type of staphylococci in clinical samples.

This study also aimed to evaluate antibiotic resistance, the ability to carry cfr, qacA/B, mecA, and vanA genes, and the diversity of staphylococcal cassette chromosome mec (SCCmec) elements in mecA-carrying isolates.

Staphylococcus spp. strains were isolated from the blood samples of children admitted to Imam Reza Hospital in Bojnurd, Northeastern Iran, between 2013 - 2019. All CoNS isolates were evaluated for resistance to vancomycin and oxacillin using agar screening and other routine anti-CoNS antibiotics using the Kirby-Bauer disk diffusion method, based on the latest Clinical and Laboratory Standards Institute guidelines. The CoNS strains were isolated based on conventional methods and polymerase chain reaction (PCR)-restriction fragment length polymorphism. The PCR was applied to determine the diversity of SCCmec elements in the CoNS isolates.

In this study, 203 isolates were confirmed as CoNS belonging to nine staphylococci spp. S. capitis and S. epidermidis were the top two common CoNS. Type III was the dominant SCCmec type in mecA+ isolates.

The findings of this study showed that CoNS isolated from blood cultures have a relatively high diversity and antibiotic resistance. Therefore, further attention should be paid to the isolation of these strains in laboratories, and they should not be easily considered as contamination.

In recent years, the global incidence of infections caused by gram-negative bacteria resistant to antibiotics has increased. This study aimed to investigate the presence and frequency of coagulase-negative Staphylococci in contact between animals and people and determine the phenotypic antimicrobial resistance profiles of coagulase-negative Staphylococci isolates from these sources.
Materials &

80 samples were collected from humans in different areas of Basrah Province, including 40 samples from human hand swabs and 40 from nasal swabs. The samples were inoculated onto mannitol salt agar and blood agar and then incubated at 37ºC for 24 hrs. Antibiotic susceptibility testing was performed using the disc diffusion method. A molecular study was done using the PCR technique.

37 samples (46.25%) were positive for staphylococcal infection. Five species, including S. sciuri, S. lentus, S. gallinarum, S. chromogen, and S. haemolyticus were identified, according to Vitek 2 kit. Staphylococci were resistant to several different antibiotics. Out of 20 amplification samples, only 12 positive samples were purified for the ermA gene region with a PCR product of 190 bp. The results also showed the presence of an ermC band with a size of 299 bp, which represents the correct expected band in 8 isolates out of all isolates.

Gram-positive organisms are increasingly identified as the source of acute clinical infection in animals and humans. Some isolates are resistant to several different antibiotics. The ermC gene, ermA gene, and both ermA and ermC genes are present in the genome of these bacteria.

Antibiotics called macrolide, lincosamide and streptogramin B (MLSB) are being used to treat staphylococci infections. Multiple pathways that impart resistance to MLSB antibiotics have been confirmed to cause clinical failure. The present work aimed to determine the frequency of constitutive and inducible clindamycin resistant among coagulase-negative staphylococci (CoNS) isolates of different clinical samples in Al-Basrah governorate, Iraq.

The 28 CoNS, traditional techniques and the Vitek®2 system were used to identify the isolates. The disk diffusion technique was used to detect methicillin resistance and antibiotic sensitivity patterns via cefoxitin, gentamicin, ciprofloxacin, amikacin, teicoplanin, linezolid, doxycycline and vancomycin disks. Erythromycin and clindamycin antibiotic disks was used to detect the inducible and constitutive clindamycin resistance as well as a D-test according to CLSI guidelines.

Among 28 CoNS isolated, the Staphylococcus aureus 11(39.29%), Staphylococcus epidermidis 7(25 %), Staphylococcus haemolyticus 4(14.29%) and Staphylococcus saprophyticus 3 (10.71%) were predominant isolated species. Out of 28 CoNS isolates, 15(53.57%) were methicillin resistant coagulasenegative staphylococci (MRCoNS) isolates and 13(46.43%) were methicillin sensitive coagulase-negative staphylococci (MSCoNS) isolates. The 15(53.57%) isolates out of 28 CoNS, showed erythromycin resistance while 6(40%) isolates out of 15 CoNS, showed inducible macrolide-lincosamide-streptogramin B (iMLSB) and 2(13.3%) of CONS isolated showed constitutive macrolide-lincosamide-streptogramin B (cMLSB).

In order to achive the best result in choosing the suitable treatment and avoiding the loses the money and time, it is better to use the D-test for inducible clindamycin resistance in the daily routine work of antibiotic susceptibility testing in hospital and private clinical laboratories.

Infectious central venous catheter (CVC) complications, including mortality and care and hospitalization costs, are still a major clinical concern. This study aimed to determine the prevalence of hemodialysis catheter infection and its risk factors among hemodialysis patients.

The present research was a descriptive, prospective cross-sectional study on hemodialysis patients in Babol hospitals during 2020 - 21. The participants’ demographic information and some relevant data on clinical variables (namely underlying diseases, cause of dialysis, and cause of catheter removal) and catheter-related variables (namely catheter location, frequency of catheter placement, and apparent signs of catheter site) were collected and recorded directly and systematically during surgery post-surgery.

One hundred and twenty-two patients with temporary double-lumen acute hemodialysis catheters for dialysis, including 56 women (45.9%), were included in this study, the mean age of whom was 58.9 ± 16.4 years. Twenty-two patients (18%) developed a catheter-induced systemic infection. There was no significant relationship between the catheter site and its removal inducing infection (P > 0.05). The frequencies of microorganisms causing catheter infection included gram-positive Staphylococcus epidermis (59%) and Staphylococcus aureus (31.8%). Moreover, there was no significant correlation between demographic variables and clinical history with systemic infection induced by catheterization.

The rate of catheter-induced infection is relatively high among patients since sterile instructions were observed during catheterization; therefore, it is recommended to pay more attention to the care and dressing of the catheter site.

This study aimed to compare the colonization of Enterococcus faecalis (E. faecalis), Escherichia coli (E. coli), Streptococcus mutans (S. mutans) and Staphylococcus aureus (S. aureus) isolated from the oral cavity on different suture materials used in oral implantology.

Patients scheduled for implant surgery were included in this study. After flap approximation, the surgical site was sutured using silk, nylon, polyglactin 910 (Vicryl®) and triclosan-coated polyglactin 910 (Vicryl® Plus) sutures in a randomized order. Seven days after surgery, the sutures were removed and incubated in bile esculin agar (for E. faecalis), MacConkey agar (for E. coli), mitis salivarius agar (for S. mutans), and mannitol salt agar (for S. aureus) at 37°C for 24 h. The colonies were then counted. Data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests.

Vicryl® sutures showed the highest accumulation of E. faecalis, followed by Vicryl® Plus, nylon, and silk. There was no significant difference between nylon and silk (P=0.5) or between Vicryl® and Vicryl® Plus (P=0.4). Vicryl® Plus sutures showed the highest accumulation of E. coli followed by Vicryl®, silk and nylon (P<0.01). Vicryl® sutures showed the highest accumulation of S. mutans, followed by Vicryl® Plus, silk, and nylon. Vicryl® Plus sutures showed the highest accumulation of S. aureus, followed by Vicryl®, nylon, and silk.

Nylon sutures showed the least microbial accumulation. Vicryl® and triclosan-coated Vicryl® Plus sutures had no advantage over the commonly used silk sutures in decreasing the number of bacteria.

Since December 2019, we have seen a significant number of cases of a novel coronavirus (2019-nCov), first identified in Wuhan China. Coronavirus might coexist with other infections such as Staphylococcus.

 Clove (Syzygium aromaticum) essential oil is a food additive with proven antimicrobial and antioxidant properties. Thus, it may be a good candidate for controlling foodborne pathogens, such as Staphylococcus aureus. The aim of the present study was to evaluate effects of sub–minimum inhibitory concentrations (MICs) of clove oil on some virulence factors of S. aureus.

The standard strain and 12 field isolates of S. aureus were obtained from our microbial collections. The broth tube dilution method was used to determine the MIC of clove oil against the isolates. Sterile 96-well flat bottom poly styrene microtiter plates were used for planktonic growth and biofilm formation assays. Slide coagulase test was used for assaying effect of clove oil on clumping factor production. Production of α- and β-hemolysins was assessed by culture on 5% bovine blood agar.

The results showed that sub-MIC concentrations of clove oil inhibited α- and β-hemolysins and biofilm production and planktonic growth of the examined isolates. However, clumping factor was not affected by sub-MIC concentrations of clove oil.

Our results indicate the favorable inhibitory effects of sub-MIC concentrations of clove oil against growth and biofilm and hemolysins production of S. aureus isolates.

 Asparaginases are known to be the cornerstone for the treatment of acute lymphoblastic leukemia (ALL) and are used for treatment in all pediatric regimens as well as in the majority of adult treatment protocols. Clinical hypersensitivity reactions against commercially available asparaginase have resulted in the failure in the treatment of ALL in more than 60% of cases. Thus, it is required to search for serologically different asparaginases from new organisms for patients exhibiting sensitivity to one formulation of asparaginase.

   The experiments were conducted in 250 mL flasks containing 100 mL of M9 broth medium and incubated at 35˚C for 48 h with shaking 100 rpm. The bacterium produced an extracellular asparaginase enzyme in which a heavy metal-rich medium was influenced—considering that this idea, enzyme activity was marked at the presence of metal salts such as FeCl3, ZnCl2, CoCl2, MgCl2, CaCl2, CuSO4, KCl and NaCl with the different concentrations as 0-3% W/V.

   In this research, we isolated a bacterium that belonged to staphylococcus species named strain MGM1 and deposited to NCBI by accession number of KT361190. The results showed that Na+, Fe2+, and K+ were inducted to enzyme production, and Zn2+ had no effects, while Cu2+, Ca2+, and Mg2+ inhibited enzyme activity when their concentrations increased up to 1%. 

This study aimed to investigate the effects of different ions on the activity of the enzyme in the blood and fluid of the body. Such compounds are vital elements in the blood, and therefore, their effect on the enzyme is very important, So This experiment suggests that asparaginase could be affected by the metals.

The radiation emitted from electromagnetic fields (EMF) can cause biological effects on prokaryotic and eukaryotic cells, including non-thermal effects.

The present study evaluated the non-thermal effects of wireless fidelity (Wi-Fi) operating at 2.4 GHz part of non-ionizing EMF on different pathogenic bacterial strains (Escherichia coli 0157H7, Staphylococcus aureus, and Staphylococcus epidermis). Antibiotic resistance, motility, metabolic activity and biofilm formation were examined.

In this case-control, a Wi-Fi router was used as a source of microwaves and also bacterial cells were exposed to Wi-Fi radiation continuously for 24 and 48 hours. The antibiotic susceptibility was carried out using a disc diffusion method on Müller Hinton agar plates. Motility of Escherichia coli 0157H7 was conducted on motility agar plates. Cell metabolic activity and biofilm formation were performed using 3-(4, 5-Dimethylthiazol-2yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and crystal violet quantification, respectively.

The exposure to Wi-Fi radiation altered motility and antibiotic susceptibility of Escherichia coli 0157H7. However, there was no effect of Wi-Fi radiation on antibiotic susceptibility of Staphylococcus aureus and Staphylococcus epidermis. On the other hand, the exposed cells, as compared to the unexposed control, showed an increased metabolic activity and biofilm formation ability in Escherichia coli 0157H7, Staphylococcus aureus and Staphylococcus epidermis.

These results proposed that Wi-Fi exposure acted on bacteria in stressful manner by increasing antibiotic resistance and motility of Escherichia coli 0157H7, as well as enhancing biofilm formation by Escherichia coli 0157H7, Staphylococcus aureus and Staphylococcus epidermis. The findings may have implications for the management of serious diseases caused by these infectious bacteria.

Acute bacterial conjunctivitis is a common, highly contagious infection in children and is usually treated empirically with broad spectrum topical antibiotics. In the current study we investigated bacteriology and antibiotic susceptibility patterns in childhood acute bacterial conjunctivitis in Western Greece. We conducted a retrospective analysis of presumed acute bacterial conjunctivitis cases in ''Karamandaneio'' Pediatric General Hospital of Patras, Western Greece, between February 1, 2013 and January 31, 2018. Specimens from the lower conjunctiva fornix were isolated from 191 cases and outcomes were analyzed to identify the pathogenic bacteria of acute bacterial conjunctivitis and their corresponding antibiotic susceptibility patterns. Patients were divided into 3 groups; Group A included neonates under 28 days of life, Group B children from 1 month to 2 years and Group C from 2 years to 14 years. Results revealed that Staphylococcus spp., Haemophilus spp. and Streptococcus spp. were the most prevalent pathogens. No significant differences in isolated pathogens were found between the age groups. Antibiotic resistance rates were higher against ampicillin, ceftriaxone, ceftazidime and sulfamethoxazole. Resistance rates to Ciprofloxacin were low while none of the evaluated isolates were resistant to vancomycin. We concluded that predominant pathogens of childhood acute bacterial conjunctivitis in Western Greece were Staphylococcus spp., Haemophilus spp. and Streptococcus spp. Continuous surveillance, focused in distinct geographic areas, is encouraged to prepare more precise protocols of empirical treatment.