Infection, Epidemiology And Medicine
Volume:8 Issue: 3, Summer 2022

Staphylococcus aureus is one of the major causes of nosocomial infections. Biofilm formation is an important virulence factor of S. aureus, leading to its high resistance to antibiotics and evasion from host defenses. This study aimed to assess the prevalence and antimicrobial resistance profile of biofilm-producing S. aureus strains and characterize genes involved in biofilm formation.

A total of 79 S. aureus strains were isolated from 1000 clinical samples and characterized using phenotypic, biochemical, and molecular tests. The biofilm production ability of isolates was examined using the microtiter assay. Moreover, the expression of genes involved in biofilm production (psm A and psm B) was screened using real-time PCR. Finally, antibiotic susceptibility testing was done using the Kirby-Bauer method and interpreted according to the CLSI M100 standard.

Out of 79 S. aureus isolates, 43 (54.4%) isolates were strong biofilm producers, 21 (26.6%) isolates were weak biofilm producers, and 15 (19%) isolates were non-adhesive. The results of real-time PCR showed that 55 (86%), 60 (93.7%), and 46 (58.2%) isolates were positive for psm A, psm B, and both genes, respectively. The results of antibiotic susceptibility testing showed that all the isolates were resistant to two or more antibiotics.

The high prevalence of biofilm-forming S. aureus strains in hospital environments could be a major health challenge with serious outcomes for hospitalized patients. Thus, it is necessary to disinfect hospital environments to reduce the risk of infection and spread of these microorganisms.

The aim of this study was to evaluate genotypes and phenotypes of antibiotic resistance in Escherichia coli (E. coli) strains isolated from poultry farms in Isfahan province, Iran.

In this study, 50 E. coli strains isolated from pericarditis and perihepatitis lesions of broilers in Isfahan (central Iran) were selected. After microbiological and biochemical tests and confirmation of bacterial colonies, the colonies were purified. The pure colonies were cultured on Müeller-Hinton culture medium and then subjected to antibiotic susceptibility testing. In the next step, DNA was extracted from the purified bacteria, and the qnrA and sul1 genes were amplified with specific primers.

The results showed that 85% of E. coli isolates were resistant to at least two antibiotics, and 6% of E. coli strains were resistant to all 13 antibiotics used in this study. E. coli isolates showed the highest resistance to enrofloxacin (70%) and the lowest resistance to gentamicin (6%). Examination of resistance genes showed that about 54% of enrofloxacin-resistant E. coli strains contained the qnrA gene, and 48% of sulfonamide-resistant E. coli strains contained the sul1 gene.

In this study, some resistant strains lacked the resistance genes studied, indicating the importance of other resistance genes in inducing resistance against sulfonamides and fluoroquinolones. Also, the lack of resistance in some strains harboring qnrA and sul1 genes indicates the importance of gene expression in mediating resistance, and that the presence of resistance genes alone is not sufficient to induce antibiotic resistance in E. coli strains.

Abnormal vaginal discharge is a common problem among pregnant women. The most common cause of these discharges is bacterial vaginosis (BV), which has numerous complications and causes problems for pregnant mothers and their fetuses. The purpose of this study was to determine the BV frequency among pregnant women referring to a gynecology clinic in Arak city using Amsel and Nugent criteria, Alberta guideline, and PCR.

This descriptive study was performed on 70 vaginal samples of pregnant women in Arak to investigate the most common causes of vaginal discharge according to Amsel and Nugent criteria and polymerase chain reaction (PCR) method using specific primers targeted towards three bacteria: Gardnerella vaginalis, Atopobium vaginae, Mobiluncus curtisii. Data were analyzed using SPSS software and Chi-square test.

In this study, ten (14.28%) out of 70 pregnant women had positive bacterial vaginosis according to Amsel criteria. According to Nugent criteria and Alberta guideline, three (4.29%) cases were diagnosed with definite BV, 20 (32.26%) cases with intermediate BV with clue cells, 42 (67.74%) cases with intermediate BV without clue cells, and finally five (4.29%) cases with negative BV. Also, according to PCR, the frequency of G. vaginalis, M. curtisii, and A. vaginae in vaginal samples was 71.42% (50 cases), 64.28% (45 cases), and 30% (21 cases), respectively. 

According to the obtained results, the prevalence of definite bacterial vaginosis was lower than that of vaginitis, and most patients suffered from nonspecific vaginitis.

The global spread of carbapenemase-producing Enterobacteriaceae represents a public health concern. This study aimed to investigate the prevalence of carbapenem resistance and the presence of some oxacillinase types and class 1-3 integrons among Enterobacter clinical isolates from an Iranian inpatient population.

Ninety Enterobacter isolates from hospitalized patients were diagnosed by microbiological methods. Antibiogram pattern was also determined. The presence of class 1-3 integrons and four types of oxacillinase genes was assessed using PCR.

Among 90 Enterobacter isolates, the most common species was E. aerogenes, (45.6%), followed by E. cloacae (30%). The highest resistance rate was against ampicillin (96.7%). Multi-drug resistance (MDR) was substantial (93%). Carbapenemase-producers were detected in 96% of carbapenem-resistant isolates by mCIM test. The frequency of evaluated genes was as follows: intI1 = 50 (55.6%), intI2 =12 (13.3%), blaoxa-1 =6 (6.7%), blaoxa-2 =5 (5.6%), blaoxa-10 =18 (20%), and blaoxa-48 =18 (20%).

Determinants of class 1 integron along with OXA-10 and OXA-48 like carbapememases are responsible for relatively considerable carbapenem resistance among isolates. This is the first report about the presence of OXA-10 and OXA-48-producing Enterobacter spp. in Iran, indicating that the prevalence of oxacillinases in the country might be on the rise.

Uropathogenic Escherichia coli is a Gram-negative bacillus that is the most common cause of urinary tract infection. E. coli has the ability to produce biofilm as an important virulence factor. Due to the lack of sufficient information about ESBL resistance genes in this geographical area, this study aimed to investigate the prevalence of ESBLs in E. coli isolates to increase our knowledge about the role of these genes and biofilm formation in inducing resistance.

139 E. coli strains were isolated from urine samples. Antibiotic susceptibility testing was performed for the isolates by disk diffusion method. ESBL production was confirmed using double-disk synergy test. Molecular detection of ESBL genes was performed using PCR. Biofilm formation assay was performed by microtiter plate method.

The most effective antibiotic against this bacterium was nitrofurantoin. Multidrug resistance was observed in 119 (85.6%) isolates. ESBL phenotype was detected in 93 (66.9%) isolates. The PCR test results showed that blaCTX, blaVEB, and blaTEM were positive in 45 (32.4%), 87 (62.6%), and 10 (7.2%) isolates, respectively. The biofilm formation assay results revealed that 65 (46.8%), 58 (41.7%), 10 (7.2%), and six (4.3%) isolates were non-, weak, moderate, and strong biofilm producers, respectively.

The high prevalence of ESBL genes is a public health concern in this region because they could be transmitted to other susceptible bacteria and induce resistance. This study showed that biofilm production could increase antibiotic resistance.

This study aimed to assess the molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from community-acquired (CA) and hospital-acquired (HA) infections in Bandar Abbas, southern Iran.

This descriptive cross-sectional study was conducted on 110 S. aureus strains isolated from 59 outpatients and 51 inpatients during 2018-2019. Antimicrobial susceptibility testing was performed using disc diffusion method. Epsilometer test was used to measure vancomycin minimum inhibitory concentration (MIC). Cefoxitin disc (30 μg) was used to screen MRSA isolates. The presence of mecA gene was examined by PCR method.  Staphylococcal cassette chromosome mec (SCCmec) types were detected in S. aureus isolates using multiplex-PCR. Chi-square and Fisher's exact tests were used to analyze the results.

Out of 110 isolates, 45 (40.9%) isolates carried the mecA gene: 20 (39.2%) isolates from inpatients and 25 (42.4%) isolates from outpatients. MRSA isolates showed the highest resistance to azithromycin (69.8%), tetracycline (60.4%), and clindamycin (32.1%), respectively. Vancomycin MIC against MRSA isolates ranged from 0.75 to 5 μg/mL. SCCmec type I, III, IV, and V were detected in 20 (44.4%), three (6.7%), 16 (35.5%), and six (13.3%) isolates, respectively.

The predominant SCCmec types were type I and type IV, which were detected in CA- and HA-MRSA isolates, respectively. No significant difference in the presence of SCCmec type III and antibiotic resistance was found between CA- and HA-MRSA isolates, indicating the possibility of cross-infection between these isolates. Developing appropriate treatment protocols to prevent the spread of MRSA infections in the community is currently an urgent need.

The fungal pathogen Candida albicans is a cause of biofilm formation in patients with oropharyngeal candidiasis. Saccharomyces boulardii is a nonpathogenic fungal probiotic that plays an important role in preventing or treating intestinal diseases. This research aimed to determine the inhibitory effect of S. boulardii probiotic yeast on biofilm formation capacity of C. albicans, which is one of the main virulence factors.

In this study, 33 oropharyngeal samples were collected from patients with suspected oropharyngeal candidiasis (OPC). The inhibitory activity of S. boulardii against biofilm formation capacity of C. albicans was investigated by crystal violet-based staining (CVS) and MTT reduction reaction. The collected data were analyzed using student's t-test in SPSS statistical software.

In this study, the probiotic yeast S. boulardii reduced the pathogenicity and virulence of C. albicans in vitro. According to the results of CVS and MTT assays, a considerable reduction (p< .001) in the biomass and viability of C. albicans biofilms was observed after 48 hours of incubation in the presence of S. boulardii extract.

There was a significant association between S. boulardii extract concentration and biofilm formation in both CVS and MTT assays. Biofilm formation decreased with increasing S. boulardii extract concentration and incubation time in both methods compared to the control group.

Toxoplasma gondii is a zoonotic parasite of increasing concern to humans and animals. Considering the side effects of drugs used to treat toxoplasmosis, it is essential to find alternative drugs.

In this study, colchicine and propranolol at four concentrations (1, 5, 10, and 15 µg/mL) were added to the RPMI medium containing peritoneal macrophages and incubated for 60 min, Then tachyzoites were added to the medium, and the efficacy rates of colchicine and propranolol in inhibiting tachyzoites entry into macrophages were evaluated after 30 and 60 min. For in vivo assay, one group received no drugs, and the second group was treated with colchicine and propranolol at different concentrations for different durations.

The in vitro experiment showed that treatment with 15 mg/mL of colchicine and propranolol for 60 min following tachyzoites addition was the most efficient method to inhibit tachyzoites penetration, indicating the efficacy rates of 80.20%±1.20 and 89.97%±1.30, respectively (p< .05). Based on the in vivo test, pretreatment with 2 mg/kg of colchicine one hour before tachyzoites injection had the best inhibitory effect (70.32%±4.07). Also, pretreatment with 2 mg/kg of propranolol 90 min before tachyzoites injection (78.54%±1.99) induced the best inhibitory effect (p< .05).

According to the results, colchicine and propranolol could inhibit tachyzoites entrance into nucleated cells in vitro and in vivo. In this study, the most efficient concentrations and times for using these substances were determined.

A short sequence of viral protein or peptide, can be used as a potential vaccine for the treatment of that virus. Considering all variants of concern (VOC), vaccine design with peptide for Severe Acute Respiratory Syndrome coronavirus 2 (SARS CoV2) is a challenging job for scientists.

In this current study, an epitope containing peptide vaccine for nonstructural protein 4 (nsp 4) of SARS CoV2 coronavirus has been predicted. With the help of a modified method for both B and T call epitope prediction, verified by molecular docking studies, linear B cell and T cell epitopes for nsp4 protein, are predicted here. Predicted epitopes are analyzed further with population coverage calculation and epitope conservancy analysis.

A short peptide sequence   74QRGGSYTNDKA84  has been selected as B cell epitope considering the scores for surface accessibility, hydrophilicity, beta turn prediction for each amino acid residues.Similarly, the peptide sequences 359 FLAHIQWMV367 and   359 FLAHIQWVMFTPLV373 are predicted as T cell epitopes for MHC-I and MHC-II molecules. These two potential epitopes can interest with HLA-A*02:01 and HLA-DRB*01:01, MHC allelic proteins respectively with lowest IC50 values.Furthermore, no amino acid mutations are observed in GISAD Global initiate on sharing all influenza data) database for alpha, beta, gamma and delta variance of concerns (VOC). Among seven amino acid point mutation of nsp 4 protein in Omicron variant, none of them is present in the peptide sequences of predicted epitope-based vaccines.

The short peptide sequences can be predicted as vaccines to prevent coronavirus infections for all variants of concerns.

Infection is one of the major threats to liver transplant patients and significantly affects associated mortality and morbidity. Serious infections are likely to occur a few months after transplantation, and most of them are bacterial. The aim of this study was to evaluate the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) bacteremia in liver transplant patients.

In this systematic review and meta-analysis, Preferred Reporting Items for systematic reviews and meta-analysis guidelines were used. International databases including PubMed, Scopus, Web of Sciences, Embase, and Cochrane were searched by related MeSH terms and keywords for studies published until July 26, 2020. The current study was registered by a pre-defined protocol in PROSPRO.

After a comprehensive literature search, 11 articles were selected for inclusion in the analysis. The prevalence of MRSA in liver transplant patients was 75% (95% CI: 58% - 89%); however, an evident heterogeneity was observed between the studies (I2= 87.84%, p< .001).

In conclusion, this study results demonstrate that the prevalence of post-transplant MRSA colonization bacteremia is high among liver transplant patients. This should be considered seriously, and efforts should be made to prevent mortality in this group of patients.