Some Virulence Factors of Staphylococci Isolated From Wound and Skin Infections in Shahrekord, IR Iran

Serological and Molecular Prevalence and Associated Risk Factors in Caprine Brucellosis, Northeastern Thailand

Brucellosis is a significant zoonotic disease with global implications for animal and human public health. This study investigated the prevalence of caprine brucellosis in 39 meat goat herds in northeastern Thailand using serological and molecular methods. Seroprevalence, determined by the modified Rose Bengal test (mRBT), was negative, indicating no detectable antibodies against Brucella. However, real-time PCR identified Brucella spp. DNA in 11 samples from 8 herds. Intraherd prevalence varied from 0.0% to 9.09%, averaging 6.73% (95% CI, 4.74-8.72). Univariate analysis revealed significant risk factors associated with brucellosis at the herd level. Larger herd size correlated with increased brucellosis odds ratio (OR: 6.30; 95% CI: 1.07-36.93; p=0.041). Herds with multiple reproductive failures, including abortion, repeat breeding, and sterile, together with weak offspring, showed higher prevalence (OR: 9.37; 95% CI: 1.17-74.84; p=0.034). Multivariable analysis identified herd sizes over thirteen as a significant risk factor (OR: 10.20; 95% CI: 1.06-97.40; p=0.044). Notably, herds where owners were aware of direct transmission risks exhibited lower infection rates (OR: 0.05; 95% CI: 0.006-0.54; p=0.012). This study underscores the complementary role of molecular techniques alongside serological tests in detecting Brucella infection accurately. The findings highlight the importance of effective herd management, reproductive health monitoring, and owner education in mitigating brucellosis transmission. Implementing robust control measures, including stringent biosecurity protocols and enhanced stakeholder awareness, is crucial for controlling brucellosis in meat goat populations.

Antibiotic Resistance Profile, Biofilm Formation Ability, and Virulence Factors Analysis of Three Staphylococcus spp. Isolates From Urine

Background Staphylococcus spp. is one of the most causative agents of urinary tract infections (UTIs). This study aimed to investigate the antibiotic resistance profile and the virulence factors, including the biofilm formation ability of Staphylococcus spp. isolates from urine. Methodology The agar disk diffusion method was used to test the susceptibility of Staphylococcus isolates to ten antibiotics. The biofilm formation ability was determined using the safranin microplate-based method, and the phospholipase, esterase, and hemolysin activities were assessed by the agar plate method. Results During the study period, a prevalence of 18.12% of urinary tract infections caused by the identified Staphylococci was obtained. All the isolated Staphylococcus aureus and S. epidermidis were resistant to cefazolin. Multi-drug resistance (MDR) was recorded in 80.01%, 81.49%, and 76.20% of S. aureus, S. epidermidis, and S. saprophyticus isolates, respectively. Most of the isolates were moderate biofilm formers, while 44.44%, 31.75%, and 30.16% were positive for phospholipase, esterase, and hemolysin activities, respectively. No relevant correlations were observed between the ability of biofilm formation and the resistance to antibiotics or the expression of virulence factors investigated. Conclusion This study shows that Staphylococcus spp. isolates from patients with clinical manifestations of UTIs expressed a high degree of virulence factors, including the ability of biofilm formation, and exhibited multi-drug resistance to the majority of antimicrobials commonly used for the treatment of Staphylococcal infections.

Saudi Honey: A Promising Therapeutic Agent for Treating Wound Infections

Treatment of wounds, especially chronic ones, is a major challenge in healthcare, with serious clinical and economic burdens. Multiple treatment approaches, including the usage of silver and iodine, have dramatically improved wound healing and reduced the incidence of infection. However, once infected by drug-resistant bacteria, treatment of wounds becomes a serious complication, with limited availability of effective antibiotic drugs, leading to high morbidity and mortality. Therefore, alternative therapeutic agents are required to address this gap in wound management. The introduction of manuka honey as a therapeutic agent against infected wounds was the result of extensive research about its activity against both planktonic and biofilm bacterial growth. Likewise, several types of Saudi honey (e.g., Sidr and Talh) showed promising in vitro and in vivo antimicrobial activity against wound pathogens. This short review summarizes literature that investigated the activity of common types of Saudi honey in relation to wound infections and explores their clinical utility.

Isolation and identification of Brucella melitensis using bacteriological and molecular tools from aborted goats in the Afar region of north-eastern Ethiopia

BACKGROUND

Infection with Brucella melitensis (B. melitensis) is one of the most important causes of abortion in goats and sheep, and also causes severe systemic disease in exposed humans. In Ethiopia, based on seroepidemiological studies, brucellosis is known to be endemic. However, there is little information on the isolation and molecular detection of Brucella species in small ruminants. Therefore, the present study was conducted in the Amibara district of Afar Region of Ethiopia to isolate and molecularly detect Brucella infection in small ruminants.

RESULTS

Out of the total 64 samples cultured, eight samples (five vaginal swabs and three milk) were positive for Brucella species based on colony morphology, growth characteristics, modified acid fast staining and biochemical tests results. Further identification using Brucella- ladder PCR method showed that four of the isolates (three from vaginal swabs and one from milk) from goats amplified fragments of 1071 bp, 794 bp, 587 bp, 450 bp and 152 bp in band size. The molecular result combined with the microbiological and biochemical characteristics of the isolates indicated that the isolates were strains of B. melitensis.

CONCLUSION

The finding of this study could suggest economic and zoonotic significance of B. melitensis and warrants for the need for control strategies in livestock and creation of awareness in the pastoral communities on the safe consumption of foods of animal origin and avoidance of physical contact with aborted materials.

Evaluation of Biofilm Formation and Presence of Ica Genes in Staphylococcus epidermidis Clinical Isolates

Objectives

Biofilm formation is one of the important features of Staphylococcus epidermidis, particularly in nosocomial infections. We aimed to investigate the biofilm production by phenotypic methods and the presence of ica genes in S epidermidis.

Methods

A total of 41 S epidermidis isolates were recovered from different clinical specimens. Biofilm formation was evaluated by microtiter plate, tube method and Congo red agar method. The presence of icaA and icaD genes was investigated by PCR. Validity of methods (sensitivity and specificity), and metrics for test performance (positive/negative predictive value, and positive/negative likelihood ratio) were determined.

Results

By both microtiter plate and tube method, 53.6% of S epidermidis isolates were able to produce biofilm, whilst only 24.4% of isolates provided a biofilm phenotype on Congo red agar plates. icaA and icaD genes were found in 100% and 95.1% of isolates, respectively. Biofilm phenotypes accounted for 4.8% by microtiter plate assay, despite the absence of the ica gene. Congo red agar and PCR exhibited a lower sensitivity (18% and 45.5%, respectively) for identifying the biofilm phenotype in comparison to microtiter plate.

Conclusion

The microtiter plate method remains generally a better tool to screen biofilm production in S epidermidis. In addition, the ability of S epidermidis to form biofilm is not always dependent on the presence of ica genes, highlighting the importance of ica-independent mechanisms of biofilm formation. The use of reliable methods to specifically detect biofilms can be helpful to treat the patients affected by such problematic bacteria.

Effect of Photodynamic Therapy on the Virulence Factors of Staphylococcus aureus

Staphylococcus aureus is a Gram-positive bacterium that is present in the human microbiota. Nevertheless, these bacteria can be pathogenic to the humans. Due to the increasing occurrence of antibiotic-resistant S. aureus strains, new approaches to control this pathogen are necessary. The antimicrobial photodynamic inactivation (PDI) process is based in the combined use of light, oxygen, and an intermediary agent (a photosensitizer). These three components interact to generate cytotoxic reactive oxygen species that irreversibly damage vital constituents of the microbial cells and ultimately lead to cell death. Although PDI is being shown to be a promising alternative to the antibiotic approach for the inactivation of pathogenic microorganisms, information on effects of photosensitization on particular virulence factors is strikingly scarce. The objective of this work was to evaluate the effect of PDI on virulence factors of S. aureus and to assess the potential development of resistance of this bacterium as well as the recovery of the expression of the virulence factors after successive PDI cycles. For this, the photosensitizer 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin tetra-iodide (Tetra-Py⁺-Me) and six strains of S. aureus [one reference strain, one strain with one enterotoxin, two strains with three enterotoxins and two methicillin resistant strains (MRSA) – one with five enterotoxins and the other without enterotoxins] were used. The effect of photosensitization on catalase activity, beta hemolysis, lipases, thermonuclease, enterotoxins, coagulase production, and resistance/susceptibility to methicillin was tested. To assess the development of resistance after successive cycles of treatment, three strains of S. aureus (ATCC 6538, 2065 MA, and SA 3 MRSA) were used. The surviving colonies of a first cycle of PDI were collected from the solid medium and subjected to further nine consecutive cycles of PDI. The results indicate that the expression of some external virulence factors is affected by PDI and enterotoxin producing strains were more susceptible to PDI than non-toxigenic strains. The surviving bacteria did not develop resistance. PDI, contrarily to traditional antibiotics, inhibited the expression of virulence factors, efficiently inactivating either highly virulent strains and low virulent S. aureus strains, inactivating also antibiotic susceptible and resistant strains, without development of photoresistance after at least 10 consecutive cycles of treatment, and so this therapy may become a strong promising alternative to antibiotics to control pathogenic microorganisms.

Synergistic Antibacterial Activity of Plant Peptide MBP-1 and Silver Nanoparticles Combination on Healing of Infected Wound Due to Staphylococcus aureus

Background:

Wound infection is a common problem in hospitals and is typically caused by the antibiotic-resistant Staphylococcus aureus, which is a major pathogen for skin and soft tissue infections worldwide.

Objectives:

The aim of this study was to investigate the synergistic antibacterial effect of plant peptide MBP-1 and silver nanoparticles on infected wounds caused by S. aureus.

Materials and Methods:

The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of MBP-1 and silver nanoparticles both on their own and in combination form were determined against S. aureus via macrodilution and microdilution methods. The synergistic antibacterial effect of silver nanoparticles and MBP-1 was investigated on infected wounds caused by S. aureus in a mouse model.

Results:

The MIC and MBC of MBP-1 were found to be 0.6 and 0.7 mg/mL, respectively. MIC and MBC of silver nanoparticles were determined to be 6.25 and 12.5 mg/L, respectively. MIC and MBC of the silver nanoparticles and MBP-1 combination were found to be 3.125 mg/mL, 0.5 mg/L; and 6.25 mg/mL, 0.6 mg/L, respectively. The infected wound healed properly after the combined use of MBP-1 and silver nanoparticles.

Conclusions:

The synergistic effect was found on the healing of infected wounds caused by S. aureus by using an MBP-1 and silver nanoparticles combination in a mouse model.