Iranian Journal of Microbiology
Volume:10 Issue: 6, Dec 2018

Breast abscesses remain as one of the most common reasons for females to come for a surgical consult. This retrospective cohort study includes both lactating and non-lactating females with breast abscesses. Due to changing trends in bacteriology of organisms, we need to reconsider our empirical choices of antibiotics. In our study, the main causative organism in breast abscess was Staphylococcus aureus with predominant species being MRSA. This is an analytical review of all breast abscesses treated in a single center from 2012 to 2015. This study included bacterial cultures, antibiotic sensitivities and resistance pattern in breast abscesses. 268 patients were included in the study. 143 (53.4%) were Lactational abscesses and 125 (46.6%) were non-Lactational abscesses. 169 (63.0%) harbored S. aureus in which 86 (50.8%) were MRSA. MRSA was the predominant organism in the Lactational group while non-Lactational group had no growth or other organisms in culture in this study. Other growing organisms were Klebsiella pneumoniae, Bacteroides, Pseudomonas, Streptococcus species and Mycobacterium tuberculosis. On comparative analysis, MRSA showed statistically a significant difference with p<0.0001, when it comes to predominant growth in lactating mothers. First line prescribed empirical antibiotics received by the patient, which is amoxicillin clavulanate, is mostly resistant. It is recommended that the institutional antibiogram targeted treatment be offered to patients with breast abscess. We also recommend ciprofloxacin with clindamycin as initial empirical therapy. MRSA was the most common organism seen in breast abscesses. Our first line treatment of antibiotics was resistant. Clindamycin and ciprofloxacin should be the preferred 1st choice for treatment.

Bacterial pathogens, in particular drug resistant strains, involved in chronic rhinosinusitis may result in treatment failure. Ultrasound waves are able to destroy bacterial population in sinus cavities and can recover patients. Twelve patients with chronic sinusitis and 10 healthy controls were treated by continuous ultrasound waves. Clinical specimens were collected before and after treatment. Serial diluted specimens were cultured on blood agar, chocolate and MacConkey agar plates for bacterial isolation. Bacterial DNA was extracted and used for Staphylococcus aureus detection using quantitative PCR. S. aureus was the most isolated bacterium (10 patients), which was eradicated from 8 patients after treatment. Using phenotypic methods at the beginning, 3 out of 10 healthy individuals were found to be positive. From 11 positive patients for S. aureus identified by real time qPCR, 9 showed significant reduction after treatment. In the healthy group, S. aureus was detected in 4 samples using qPCR, but they were clean at the second sampling. According to our phenotypic and molecular experiments, continuous ultrasound treatment effectively reduced the bacterial population in studied patients (p < 0.01). This was a hopeful basis for doing more studies with ultrasound therapy as a treatment option.

Escherichia coli O157:H7 is one of the most important food pathogens that produces colitis and bloody urine in humans. The Stx2B subunit is considered as one of the candidates for vaccine due to its immunogenic and adjuvant properties. Designing a mucosal vaccine using nanoparticles for protecting the antigen against degradation and controlling the release of antigen are important. The objective of the current study was to prepare nanoparticles containing the Stx2B subunit of E. coli O157:H7 and evaluation of its immunogenicity in the mouse model. E. coli BL21 DE3 and pET28a-stxB were used for expression of the stx2b gene. After inducing gene expression, purification of the Stx2b protein was performed. Then, chitosan nanoparticle containing recombinant Stx2B was prepared and administered to BALB/c mice. IgA and IgG titers in serum and IgA titers in feces of immunized and control mice were evaluated by the ELISA method. After expression and purification of the Stx2B recombinant protein, an expected band of 13 kDa was observed on the SDS-PAGE gel and confirmed by Western Blot analysis. The size of the nanoparticle containing Stx2B was 290 nm. In the immunized mice, IgG and IgA titers were significantly increased. The immunized mice were challenged against E. coli O157:H7 Stx+ and the shedding analysis showed that colonization of bacteria in the intestinal tract decreased. Oral administration of nanoparticles containing Stx2B as a candidate for the vaccine can induce a systemic and mucosal immune response against Stx2 toxin and can provide acceptable protection.

Burn wounds are one of the most important health problems all over the world because infection after burn can delay wound healing. Treating burn wounds with granulocyte-colony stimulating factor (G-CSF) is known to improve healing of injured tissue. In addition, colistin is prescribed as an effective treatment. The aim of this study was to evaluate the effect of G-CSF and colistin alone or in combination with G-CSF on wound healing of Acinetobacter baumannii (A. baumannii) infected burns. This study was performed between January 2016 and April 2018. Burn wounds were experimentally induced in 36 mice. The wounds were inoculated with A. baumannii. In a 7-day period, burn wounds in each group were daily treated with subcutaneous injections (0.1 ml) of saline, G-CSF, colistin, and G-CSF plus colistin. After killing the animals, the size of the wound, number of leukocytes in the skin and microbial growth were evaluated. A value of p ≤ 0.05 was considered statistically significant. Wound healing in the G-CSF plus colistin group was significantly higher than the control group and the G-CSF group (P = 0.023 and P = 0.033, respectively). In G-CSF+colistin group, the number of leukocytes was higher than the control group considerably (P = 0.007). On the 7th day of treatment, number of positive bacterial cultures in the colistin and the G-CSF plus colistin groups was lower than other groups with a significant difference. Concurrent consumption of G-CSF and antibiotics can control burn infection and enhance the immune system towards wound healing.

This study was conducted to compare the effect of acticoat and agcoat dressing (2 types of silver nano-crystalline dressings) in the treatment of burn wounds. Infection is one of the most important causes of death in patients with major burn. Despite using different prevention methods, including prophylaxis antibiotics with broad-spectrum antibiotics, no method has been found to prevent this dangerous complication for burn patients. Topical silver sulfadiazine is one of the best topical antibiotics in infection control of burn wounds, and other forms of AG dressings are also useful. Their advantages are slow releasing, further-half-life, less frequent dressing change, and less pain during replacement. In this study, 30 patients with infected full thickness burn wound were selected. The patients’ age range was 18-85 years, with the mean age of 39.7-17.27. Every patient's wound was divided into 2 parts randomly, one part was dressed with agcoat and the other with acticoat. Sampling of the 2 parts was done before dressing and after the third and seventh day of dressing. The positive outcome of the first day culturing before silver dressing was 80% and 76.7% for agcoat and acticoat, respectively. However, on the third day, it decreased to 30% and 33.3%, respectively. On the seventh day, it further decreased to 20% in both groups, and the percentage of bacterial growth reduction was not significant. Based on the results of this study, silver agcoat dressing was as effective as acticoat dressing in preventing burn wound infection.

Traditional culture methods for detection of food-borne pathogens, a major public health problem, are simple, easily adaptable and very practical, but they can be laborious and time consuming. In this study, we eliminated culturing steps by developing a new separation method and therefore, decreased the detection time of food-borne pathogens (Salmonella enterica serovar Typhimurium, Escherichia coli O157:H7 and Listeria monocytogenes) to a few hours. We used alkaline water and different alkaline buffers to elute bacteria from the lettuce surface as a model for ready-to-eat vegetables. Buffers used were as follows: 1) 0.05 M glycine; 2) 0.05 M glycine -100 mM Tris base -1% (w/v) beef extract; 3) buffer peptone water; 4) buffer phosphate saline. Buffers were adjusted to pH of 9, 9.5 and 10. In order to elute the bacteria, the lettuce pieces were suspended into buffers and shacked for 30, 45 and 60 min. Moreover, a multiplex PCR method for the simultaneous detection of food-borne pathogens was performed. The results showed that buffer peptone water at pH 9.5 for 45 min have high ability to elute bacteria from the lettuce surface and the bacteria can be detected using multiplex PCR. We developed a new rapid and efficient method for simultaneous separation of food-borne pathogens. This method eliminates culturing stages and permits the detection and identification of target pathogens in a few hours.

Essential oils are used for controlling and preventing human diseases and the application of those can often be quite safe and effective with no side effect. The essential oils have been found to have antiparasitic, antifungal, antiviral, antioxidant and especially antibacterial activity including antibacterial activity against tuberculosis. In this study the chemical composition and anti-TB activity of essential oil extracted from Levisticum officinale has been evaluated. The essential oil of L. officinale was obtained by the hydro distillation method and the oil was analyzed by GC-FID and GC-MS techniques. The antibacterial activity of essential oil was evaluated through Minimum Inhibitory Concentration (MIC) assay using micro broth dilution method against multidrug-resistant Maycobacterium tuberculosis. The molecular modeling of major compounds was evaluated through molecular docking using Auto Dock Vina against-2-trans-enoyl-ACP reductase (InhA) as key enzyme in M. tuberclosis cell wall biosynthesis. The hydrodistillation on aerial parts of L. officinale yielded 2.5% v/w of essential oil. The major compounds of essential oil were identified as α-terpinenyl acetate (52.85%), β- phellandrene (10.26%) and neocnidilide (10.12%). The essential oil showed relatively good anti-MDR M. tuberculosis with MIC = 252 μg/ml. The results of Molecular Docking showed that affinity of major compounds was comparable to isoniazid. The essential oil of aerial parts extracted from L. officinale was relatively active against MDR M. tuberculosis, and molecular docking showed the major compounds had high affinity to inhibit 2-trans-enoyl-acyl carrier protein reductase (InhA) as an important enzyme in M. tuberculosis cell wall biosynthesis.

The use of plants for the synthesis of nanoparticles has received attention. The present study aimed to evaluate the antibacterial effects of silver nanoparticles synthesized by Verbena officinalis leaf extract against Yersinia ruckeri, Vibrio cholerae and Listeria monocytogenes. Silver nanoparticles were obtained by reacting silver nitrate solution 2 mM and V. officinalis leaf extract. The AgNPs were characterized by UV-visible spectrophotometer, scanning electron microscopy (SEM), and Fourier transform infrared spectrometer (FTIR). To determine minimum inhibitory concentration and test antibiogram of nanoparticle synthesized, broth micro dilution and agar well diffusion methods were used, respectively. The zones of bacterial inhibition were 16 ± 0.5 and 9.16 ± 0.28 mm against Y. ruckeri and L. monocytogenes using 10 and 0.62 mg/mL AgNPs, respectively. Among the studied bacterial species, silver nanoparticles were more effective on Y. ruckeri and L. monocytogenes and less effective on V. cholerae. The highest MIC and MBC of AgNPs (2.5 and 5 mg/mL) were observed for V. cholerae. The lowest MIC and MBC of AgNPs (0.32 and 0.62 mg/mL) were observed for Y. ruckeri, respectively. The MIC and MBC of AgNPs were found to be 1.25 and 2.5 mg/mL for L. monocytogenes. The results clearly indicated that V. officinalis AgNPs have potential antimicrobial activity against Gram-positive and Gram-negative bacteria.

Larval therapy refers to the use of Lucilia sericata larvae on chronic wounds, which is a successful method of chronic wounds treatment. The secretions of these larvae contain antibacterial compounds and lead to death or inhibition of bacterial growth.

In this study, we investigated the antibacterial effects of Lucilia sericata larvae secretions which were in sterilized and multi antibiotic-resistant bacteria-treated forms on Gram-positive Bacillus subtilis bacteria and Gram-negative Escherichia coli bacteria. In the following, we evaluated changes in gene expression of lucifensin and attacin during treatment with multi antibiotic-resistant bacteria. Investigation of the antibacterial effect was carried out using optical absorption and antibiotic disk diffusion in order to study the expression of the aforementioned genes.

The results of this study showed that E. coli-treated larvae were able to inhibit the growth of E. coli and secretions of B. subtilis-treated larvae and were also able to inhibit the growth of B. subtilis. Gene expression of antibacterial peptides in multi antibiotic-resistant bacteria-treated larvae was increased in comparison to non-treated larvae.

Due to the significant antibacterial potency of bacteria-treated larvae secretions, the secretions can be a suitable candidate as a drug against antibiotic resistant bacteria, but additional tests are required. Since the antimicrobial peptides of insects have not yet produced any resistance in human pathogenic bacteria, they can be considered as a promising strategy for dealing with resistant infections.

One of the most important antibiotic-resistant bacteria is methicillin-resistant Staphylococcus aureus (MRSA) biofilm that has caused significant problems in treating the patients. Therefore, the aim of this study was to evaluate the levels of expression of genes involved in biofilm formation in MRSA (ATCC 33591) while being treated by a combination of Artemisia aucheri and Artemisia oliveriana. The minimum inhibitory concentration (MIC) of ethanolic extract of A. aucheri and A. oliveriana and also the minimum inhibitory concentration of combination of both extracts were 512, 1024 and 256 μg/ml, respectively; then at concentrations lower than the MIC, expression levels of the desired genes were determined by Real Time PCR. Based on results, using a combination of two ethanolic extracts had a significant effect on expression of genes involved in biofilm formation in MRSA. The expression level of icaA at 4, 8, 16 h after being treated by herbal extracts of A. aucheri and A. oliveriana was 0.293, 0.121, 0.044, respectively. The expression level of icaD was 0.285, 0.097, 0.088, respectively, while that of ebps was 0.087, 0.042, 0.009 at 4, 8 and 16 h, respectively. This study provided evidence that ethanol extract of A. oliveriava and A. aucheri can inhibit the biofilm formation of S. aureus. As a traditional Iranian medicine, A. oliveriava and A. aucheri extracts have a potential antibiofilm formation against MRSA strains.

The aim of this study was to determine the effect of zinc oxide nanoparticle (ZnO-np) solution in the surface catheter on C. albicans adhesion and biofilm formation. Out of 260 isolates from urinary catheter, 133 were determined as C. albicans by common phenotypic and genotyping methods. ZnO nanoparticles with 30 nm were made by the sol-gel method, which was confirmed by XRD (X-ray diffraction) and scanning electron microscope (SEM) methods. Candidal adhesion and biofilm assays were performed on catheter surfaces for 2 and 48 hours, respectively. The effect of sub-MIC (minimum inhibitory concentrations) and MIC concentrations of ZnO-np on biofilm formation was evaluated after 24 hours using Crystal violet (CV), colony-forming unit (CFU), and SEM. Out of 133 C. albicans isolates, 20 (15%) fluconazole-resistant and 113 (85%) susceptible isolates were determined by the disk diffusion method. Results showed that both isolates adhered to biofilm formation on the catheter surfaces. A significantly (P< 0.05) higher number of CFUs was evident in fluconazole-resistant biofilms compared to those formed by susceptible isolates. ZnO-np reduced biofilm biomass and CFUs of dual isolate biofilms (P< 0.05). ZnO nanoparticles had a significantly (P< 0.05) greater effect on reducing fluconazole-resistant C. albicans biofilm biomass compared to susceptible isolates. Zno-np exhibits inhibitory effects on biofilms of both isolates. These findings provide an important advantage of ZnO that may be useful in the treatment of catheter-related urinary tract infection.

Rapid confirmation of dermatomycoses is desirable, as it allows the clinicians to initiate appropriate therapy immediately. In this study, the utility of a novel contrast stain, Chicago sky blue stain, was compared with potassium hydroxide mount and calcofluor white stain to determine the causative fungal elements in the rapid detection method. In this survey, 189 samples of suspected dermatomycosis infections were assessed in 3 incubation times of 30 minutes, 2 hours, and > 6 hours. Positive cases were shown in Chicago sky blue 6B (55%), calcofluor white (53.4%), and potassium hydroxide (36%), with 30-minute incubation. Positive results increased in other incubation times. Sensitivity, specificity, PPV, NPV and accuracy of Chicago sky blue 6B were 97%, 100%, 100%, 96% and 98% and, for potassium hydroxide, they were 66%, 98%, 97%, 98%, 80% versus CFW, respectively. This study provides evidence that the Chicago sky blue 6B stain is a simple, fast and cost-effective method.

Cervical cancer is an important cause of death in women worldwide (1, 2). Cancer is a disease that may be caused by many factors that affect gene activity through genetic and epigenetic changes like DNA methylation. DNA promoter methylation contributes to the chromatin conformation that may be repressing transcription of the human papilloma virus type16 (HPV-16), which is prevalent in the etiology of cervical carcinoma. In the present study, we aimed to investigate DNA methylation target sites in promoter region of both high-risk and low risk HPVs. Methylation pattern of E6 promoter in low-risk HPV (type 11) and high-risk HPV (type 16 and 18) was examined by Bisulfite Sequencing PCR (BSP) method. Based on the results, methylation status of high-risk and low-risk HPV-E6 promoter is different. It was revealed that CpG dinucleotides were unmethylated in type 16 and 18 target sequences, whereas in HPV-E6 type 11 all of CpG dinucleotides were methylated except one of them. The result suggested that a significant correlation between methylation status and HPV-induced cervical carcinogenesis, and promoter of HPV-16 and 18 E6 has minimal methylation in comparison with low-risk HPV-11.