Global prevalence of mutation in the mgrB gene among clinical isolates of colistin-resistant Klebsiella pneumoniae: a systematic review and meta-analysis.

Background: Colistin is used as a last resort for managing infections caused by multidrug-resistant bacteria. However, the high emergence of colistin-resistant strains has restricted the clinical use of this antibiotic in the clinical setting. In the present study, we evaluated the global prevalence of the mutation in the mgrB gene, one of the most important mechanisms of colistin resistance in Klebsiella pneumoniae. Methods: Several databases, including Scopus, Medline (via PubMed), and Web of Science, were searched (until August 2023) to identify those studies that address the mgrB mutation in clinical isolates of K. pneumoniae. Using Stata software, the pooled prevalence of mgrB mutation and subgroup analyses for the year of publication, country, continent, mgrB mutation types, and detection methods of mgrB mutation were analyzed. Results: Out of the 115 studies included in the analysis, the prevalence of mgrB mutations in colistin-resistant K. pneumoniae isolates was estimated at 65% of isolates, and mgrB variations with insertional inactivation had the highest prevalence among the five investigated mutations with 69%. The year subgroup analysis indicated an increase in mutated mgrB from 46% in 2014 to 61% in 2022. Europe had the highest prevalence of mutated mgrB at 73%, while Africa had the lowest at 54%. Conclusion: Mutations in the mgrB gene are reported as one of the most common mechanisms of colistin resistance in K. pneumoniae, and the results of the present study showed that 65% of the reported colistin-resistant K. pneumoniae had a mutation in this gene.

Inhibitory effect of natural compounds on quorum sensing system in Pseudomonas aeruginosa: a helpful promise for managing biofilm community.

Pseudomonas aeruginosa biofilm is a community of bacteria that adhere to live or non-living surfaces and are encapsulated by an extracellular polymeric substance. Unlike individual planktonic cells, biofilms possess a notable inherent resistance to sanitizers and antibiotics. Overcoming this resistance is a substantial barrier in the medical and food industries. Hence, while antibiotics are ineffective in eradicating P. aeruginosa biofilm, scientists have explored alternate strategies, including the utilization of natural compounds as a novel treatment option. To this end, curcumin, carvacrol, thymol, eugenol, cinnamaldehyde, coumarin, catechin, terpinene-4-ol, linalool, pinene, linoleic acid, saponin, and geraniol are the major natural compounds extensively utilized for the management of the P. aeruginosa biofilm community. Noteworthy, the exact interaction of natural compounds and the biofilm of this bacterium is not elucidated yet; however, the interference with the quorum sensing system and the inhibition of autoinducer production in P. aeruginosa are the main possible mechanisms. Noteworthy, the use of different drug platforms can overcome some drawbacks of natural compounds, such as insolubility in water, limited oral bioavailability, fast metabolism, and degradation. Additionally, drug platforms can deliver different antibiofilm agents simultaneously, which enhances the antibiofilm potential of natural compounds. This article explores many facets of utilizing natural compounds to inhibit and eradicate P. aeruginosa biofilms. It also examines the techniques and protocols employed to enhance the effectiveness of these compounds.

An overview of case reports and case series of pulmonary actinomycosis mimicking lung cancer: a scoping review.

Background: Pulmonary actinomycosis (PA) is a rare type of Actinomyces infection that can be challenging to diagnose since it often mimics lung cancer. Methods: Published case reports and case series of PA in patients with suspicion of lung cancer were considered, and data were extracted by a structured search through PubMed/Medline. Results: After analyzing Medline, 31 studies were reviewed, from which 48 cases were extracted. Europe had the highest prevalence of reported cases with 45.1%, followed by Asia (32.2%), America (19.3%), and Africa (3.2%). The average age of patients was 58.9 years, and 75% of all patients were above 50 years old. Male patients (70%) were predominantly affected by PA. The overall mortality rate was 6.25%. In only eight cases, the causative agent was reported, and Actinomyces odontolyticus was the most common isolated pathogen with three cases. Based on histopathological examination, 75% of the cases were diagnosed, and the lobectomy was performed in 10 cases, the most common surgical intervention. In 50% of the cases, the selective antibiotics were intravenous and oral penicillin, followed by amoxicillin (29.1%), amoxicillin-clavulanic acid, ampicillin, levofloxacin, and doxycycline. Conclusion: The non-specific symptoms resemble lung cancer, leading to confusion between PA and cancer in imaging scans. Radiological techniques are helpful but have limitations that can lead to unnecessary surgeries when confusing PA with lung cancer. Therefore, it is important to raise awareness about the signs and symptoms of PA and lung cancer to prevent undesirable complications and ensure appropriate treatment measures are taken.

Prevalence of Brucella endocarditis: A systematic review and meta-analysis.

Background: Endocarditis caused by Brucella infection is one of this infection's complications, including a high mortality rate. However, studies on the prevalence of this complication have been limited to some case reports. This study investigated the prevalence of Brucella endocarditis globally using a systematic review and meta-analysis. Methods: PubMed, Scopus, and Web of Science databases were searched using appropriate keywords until September 2022. All studies reporting the prevalence of endocarditis in patients with brucellosis were included in this current study. To investigate the pooled prevalence of Brucella endocarditis, random model was used in comprehensive meta-analysis software. Results: A total of 25 studies met the inclusion criteria and were included in the systematic review and meta-analysis. The prevalence of Brucella endocarditis was 1.3%, and the death rate was 26.5%. The results did not show a significant difference in the prevalence of this complication in different regions. Conclusion: According to this study's results, the prevalence of Brucella endocarditis is low, but it includes a large percentage of the deaths of affected patients. To complete our understanding of this complication and its management, more research should be done to investigate the effect of other factors, such as age and gender.

Clinical presentations, diagnosis, management, and outcomes of renal mucormycosis: An overview of case reports.

Background: Renal mucormycosis (RM) is a rare presentation of invasive mucormycosis with a high mortality rate. There is no single systematic review of the literature that indicates the different clinical aspects of RM. Methods: A systematic search of PubMed/Medline was performed to collect individual case reports of RM in patients of all ages published between 2010 and April 2022. Results: Seventy-one individual cases were detected through PubMed bibliographic database searches, with a final assessment performed on 60 patients with RM. India and Asia had the largest number of reported cases, with 30 (50%) and 42 (70%) reports, respectively. Also, 74 and 26% of the patients with a mean age of 33 years were male and female, respectively. RM showed 44% mortality rate in the analyzed cases. Immunosuppressive agent therapy followed by tissue transplantation (kidney and liver) and diabetes were the most remarkable risk factors in patients. Nevertheless, 22% of the patients were immunocompetent with no apparent underlying condition. COVID-19 positivity was detected in eight adult patients with an 87% mortality rate. The most common signs of infection were fever, flank pain, and oliguria; additionally, isolated RM was reported in 57% of the cases. In 55% of the patients, histopathologic examination alone was sufficient to diagnose RM, whereas molecular methods and culture were used in only 18 and 35% of patients, respectively. Surgery alone, surgery plus anti-infection therapy, and anti-infection therapy alone were used in 12, 60, and 13% of patients, respectively. Furthermore, 15% of the patients died before any treatment. Conclusion: The early diagnosis of RM is necessary. In this regard, the use of molecular-based diagnostic assays can help identify the fungus at the genus and species levels and use an appropriate treatment in the shortest possible amount of time. Because of the increase in antibiotic resistance in recent years, determining microbial susceptibility tests can lead to the better infection management. Additionally, withdrawal of immunosuppressant, appropriate surgical intervention, and antifungal therapy are the main factors associated with a successful outcome in RM.

Molecular determination of O25b/ST131 clone type among extended spectrum ß-lactamases production Escherichia coli recovering from urinary tract infection isolates.

BACKGROUND: Escherichia coli (E. coli) O25b/ST131 clone causes urinary tract infection (UTI) and is associated with a broad spectrum of other infections, such as intra-abdominal and soft tissue infections, that can be affecting bloodstream infections. Therefore, since O25b/ST131 has been reported in several studies from Iran, in the current study, we have investigated the molecular characteristics, typing, and biofilm formation of O25b/ST131 clone type E. coli collected from UTI specimens. METHODS: A total of 173 E. coli isolates from UTI were collected. The susceptibility to all fourth generations of cephalosporins (cefazolin, cefuroxime, ceftriaxone, cefotaxime, ceftazidime, cefepime) and ampicillin, ampicillin-sulbactam and aztreonam was determined. Class A ESBLs, class D ESBL and the presence of pabB gene screenings to detect of O25b/ST131 clone type were performed by using of PCR. Biofilm formation was compared between O25b/ST131 isolates and non-O25b/ST131 isolates. Finally, ERIC-PCR was used for typing of ESBL positive isolates. RESULTS: Ninety-four ESBL positive were detected of which 79 of them were O25b/ST131. Antimicrobial susceptibility test data showed that most antibiotics had a higher rate of resistance in isolates of the O25b/ST131 clonal type. Biofilm formation showed that there was a weak association between O25b/ST131 clone type isolates and the level of the biofilm formation. ERIC-PCR results showed that E. coli isolates were genetically diverse and classified into 14 groups. CONCLUSION: Our results demonstrated the importance and high prevalence of E. coli O25b/ST131 among UTI isolates with the ability to spread fast and disseminate antibiotic resistance genes.

The role of Staphylococcus aureus enterotoxin B in chronic rhinosinusitis with nasal polyposis.

CRS with nasal polyps (CRSwNP) is a multifactorial disease, and various etiological factors like bacterial superantigens are known to develop this disease. Recent studies reported that Staphylococcus aureus nasal colonization was detected in 67% of the patients with CRSwNP. Moreover, it was reported that specific IgE against S. aureus enterotoxins are discovered in almost half of the nasal tissue homogenates from nasal polyps. Thus, investigations have highlighted the role of staphylococcal enterotoxins, especially enterotoxin B (SEB), in pathogenesis of CRSwNP. The destruction of mucosal integrity was reported as a main SEB-related pathogenic mechanisms in CRSwNP. SEB activates Toll Like Receptor 2 and triggers the production of pro-inflammatory cytokines; furthermore, it induces reactive oxygen species and endoplasmic reticulum stress-induced inflammation that may cause epithelial cell integrity disruption and enhance their permeability. SEB-induced Type 2/Th2 pathway results in degranulation of eosinophils, cationic proteins production, and localized eosinophilic inflammation. Furthermore, SEB may be involved in the expression of RORC and HIF-1α in Tregs and by maintaining the inflammation in sinonasal mucosa that could have a main role in the pathogenesis of nasal polyposis. Different in vitro findings were confirmed in animal studies; however, in vivo analysis of SEB-induced nasal polyps and CRS remains unfulfilled due to the lack of appropriate animal models. Finally, after elucidating different aspects of SEB pathogenesis in CRSwNP, therapeutic agents have been tested in recent studies with some encouraging results. The purpose of this article is to summarize the most important findings regarding SEB-induced CRS and nasal polyposis. Video Abstract.

Mutation in mgrB is the major colistin resistance mechanism in Klebsiella pneumoniae clinical isolates in Tehran, Iran.

Colistin is considered as one of a last resort antimicrobial agent against multidrug-resistant Gram-negative bacteria including Escherichia coli and Klebsiella pneumoniae. However, the recent emergence of colistin resistance (ColR) worldwide that severely restricts therapeutic options is a serious threat to global public health. In this study we have investigated the molecular determinants in ColR K. pneumoniae isolates collected from clinical specimens. A total of 98 E. coli and 195 K. pneumoniae clinical isolates were collected from two hospitals from August 2018 to December 2019 in Tehran, Iran. Colistin susceptibility and minimum inhibitory concentrations (MIC) were determined according to the Clinical and Laboratory Standards Institute by disk diffusion method, and microdilution method, respectively. For isolates with colistin MIC ≥4 µg mL-1, PCR was performed for the detection of mcr-1 to mcr-4 genes. Moreover, nucleotide sequences of mgrB, phoP, phoQ, pmrA, and pmrB genes were determined by sequencing. Finally, the transcriptional level of pmrK and pmrC genes was evaluated by quantitative reverse transcription PCR (RT-qPCR). None of the E. coli isolates were resistant to colistin while 21 out 195 K. pneumoniae isolates were identified as resistant, 19 of which carried mutation in the mgrB gene. Three different mutations were observed in the pmrB gene in 3 K. pneumoniae isolates. None of the ColR isolates showed alternations in pmrA, phoP, and phoQ genes. Furthermore, none of the plasmid-encoding genes were detected. Transcriptional level of the pmrK gene increased in all ColR isolates meanwhile, pmrC overexpression was detected in 16 out 21 (76.19%) isolates. Eventually, all ColR isolates were susceptible to tigecycline. Our results demonstrated that the alternation of mgrB gene is the main mechanism related to colistin resistance among ColR K. pneumoniae isolates in this study.

Novel strategies for inhibition of bacterial biofilm in chronic rhinosinusitis.

An important role has been recently reported for bacterial biofilm in the pathophysiology of chronic diseases, such as chronic rhinosinusitis (CRS). CRS, affecting sinonasal mucosa, is a persistent inflammatory condition with a high prevalence around the world. Although the exact pathological mechanism of this disease has not been elicited yet, biofilm formation is known to lead to a more significant symptom burden and major objective clinical indicators. The high prevalence of multidrug-resistant bacteria has severely restricted the application of antibiotics in recent years. Furthermore, systemic antibiotic therapy, on top of its insufficient concentration to eradicate bacteria in the sinonasal biofilm, often causes toxicity, antibiotic resistance, and an effect on the natural microbiota, in patients. Thus, coming up with alternative therapeutic options instead of systemic antibiotic therapy is emphasized in the treatment of bacterial biofilm in CRS patients. The use of topical antibiotic therapy and antibiotic eluting sinus stents that induce higher antibiotic concentration, and decrease side effects could be helpful. Besides, recent research recognized that various natural products, nitric oxide, and bacteriophage therapy, in addition to the hindered biofilm formation, could degrade the established bacterial biofilm. However, despite these improvements, new antibacterial agents and CRS biofilm interactions are complicated and need extensive research. Finally, most studies were performed in vitro, and more preclinical animal models and human studies are required to confirm the collected data. The present review is specifically discussing potential therapeutic strategies for the treatment of bacterial biofilm in CRS patients.

Prevalence and molecular mechanisms of colistin resistance in Acinetobacter baumannii clinical isolates in Tehran, Iran.

Colistin is one of the last remaining active antibiotics against multidrug resistant Gram-negative bacteria. However, several recent studies reported colistin-resistant (ColR) Acinetobacter baumannii from different countries. In the current study, we investigated molecular mechanisms involved in colistin resistance in A. baumannii isolates from different clinical samples.A total of 110 clinical A. baumannii isolates were collected from two hospitals in Tehran. Minimum inhibitory concentrations (MICs) were determined by broth microdilution according to the Clinical and Laboratory Standards Institute. For the ColR isolates, mutation was detected in pmrA, pmrB, lpxA, lpxC, and lpxD genes using the polymerase chain reaction (PCR) and sequencing. Moreover, the relative expression of the pmrC gene was calculated using quantitative reverse transcription PCR. Three colistin resistant isolates were identified with MIC between 8 and 16 µg/mL and were resistant to all the tested antimicrobial agents. All the three isolates had a mutation in the pmrB, pmrA, lpxA, lpxD, and lpxC genes. Moreover, the overexpression of pmrC gene was observed in all isolates. Our results showed that the upregulation of the PmrAB two component system was the primary mechanism linked to colistin resistance among the studied colistin resistant A. baumannii isolates.

A systematic review of case reports of hepatic actinomycosis.

BACKGROUND: Hepatic Actinomycosis (HA) is one of the infections that causes disorders in patients when diagnosed untimely and inappropriately. METHODS: Case reports on HA in patients published between 2000 and April 2020 were gathered by carrying out a structured search through PubMed/Medline. RESULTS: Through a survey of the Medline database, 130 studies were identified and then, 64 cases with HA were included in the final analysis. Asia had the largest share of cases with 37.5% (24 reports), followed by Europe and the Americas. Affected patients were predominantly males (64%) and the overall mortality rate was 1% with only one male patient in his 50 s dying. Nearly all patients (92%) were immunocompetent. However, in four patients, the use of immunosuppressive medication led to depression of the immune system. Most of the patients (80%) experienced complications. In terms of the complications, the most frequent ones were previous history of abdominal surgery (32%) and foreign bodies in the abdominopelvic region (20%). Actinomyces israelii was the most common pathogen isolated from patients. Abdominal pain (66%), fever (62%), weight loss (48%), night sweat, malaise, and anorexia (14%) over about 3.1 months were the most frequently reported clinical symptoms. Extension to one or more surrounding organs was evident in 18 patients (28%). Histopathologic examination confirmed infection in 67% of the patients and samples obtained from liver puncture biopsy (32%) were most frequently used in diagnosis. Surgery or puncture drainage + anti-infection was the most common method to treat patients and penicillin, Amoxicillin, Doxycycline, and ampicillin were the most frequently used drugs to control infection. CONCLUSION: HA should be considered in patients with a subacute or chronic inflammatory process of the liver. With accurate and timely diagnosis of infection, extensive surgery can be prevented.

An overview of possible pathogenesis mechanisms of Alternaria alternata in chronic rhinosinusitis and nasal polyposis.

Chronic Rhinosinusitis (CRS) is a multifactorial disease, and different etiologies like metabolism and immunity disorders, bacterial superantigens, biofilms, and fungal allergens are known to develop this disease, especially the CRS with nasal polyps. Alternaria alternata (Alternaria) is one of the most prevalent airborne fungal species in the nasal discharge, which might have vigorous immunologic activities in nasal epithelial cells and play an essential role in the pathogenesis of CRS. Moreover, the interaction between this fungus and the innate and adaptive immune systems leads to the development of chronic inflammation. This inflammation may consequently instigate the CRS and nasal polyposis. The attenuation of surfactant protein synthesis or intracellular reserves and mucus hypersecretion could prevent the clearance of Alternaria from sinuses and may be correlated with colonization and re-infection of airborne fungi. Furthermore, higher expression of cathelicidin, thymic stromal lymphopoietin, toll-like receptors, and T helper 2-dominant immune responses can result in an IgE-mediated pathway activation and eosinophils degranulation. Moreover, higher local Alternaria-specific IgE was shown to be correlated with eosinophilic cationic proteins and might relate to nasal polyps. However, the role of genetic and environmental factors affecting CRS and nasal polyposis is not well studied. Likewise, further animal and clinical studies are required to better understand the role of Alternaria in CRS disease. The current article reviews the recent findings around the Alternaria-induced CRS and nasal polyposis.

Bacteriophage therapy for inhibition of multi drug-resistant uropathogenic bacteria: a narrative review.

Multi-Drug Resistant (MDR) uropathogenic bacteria have increased in number in recent years and the development of new treatment options for the corresponding infections has become a major challenge in the field of medicine. In this respect, recent studies have proposed bacteriophage (phage) therapy as a potential alternative against MDR Urinary Tract Infections (UTI) because the resistance mechanism of phages differs from that of antibiotics and few side effects have been reported for them. Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis are the most common uropathogenic bacteria against which phage therapy has been used. Phages, in addition to lysing bacterial pathogens, can prevent the formation of biofilms. Besides, by inducing or producing polysaccharide depolymerase, phages can easily penetrate into deeper layers of the biofilm and degrade it. Notably, phage therapy has shown good results in inhibiting multiple-species biofilm and this may be an efficient weapon against catheter-associated UTI. However, the narrow range of hosts limits the use of phage therapy. Therefore, the use of phage cocktail and combination therapy can form a highly attractive strategy. However, despite the positive use of these treatments, various studies have reported phage-resistant strains, indicating that phage-host interactions are more complicated and need further research. Furthermore, these investigations are limited and further clinical trials are required to make this treatment widely available for human use. This review highlights phage therapy in the context of treating UTIs and the specific considerations for this application.

Molecular Characterization of Tigecycline Non-Susceptibility among Extensively Drug-Resistant Acinetobacter baumannii Isolates of Clinical Origin.

INTRODUCTION: Tigecycline (TGC) is one of the last-resort therapeutic agents for treating infections caused by extensively drug resistant Acinetobacter baumannii isolates. Although resistance to TGC is not common, non-susceptible A. baumannii (NSAB) isolates have been described. In the current study, we aimed to assess the molecular mechanisms mediating TGC non-susceptibility in 5 clinical isolates of A. baumannii with reduced susceptibility to TGC. METHODS: Susceptibility of isolates to TGC as well as various classes of antibiotics was evaluated by broth dilution and disk diffusion methods, respectively. The presence of tetX and tetX1 genes was investigated by PCR. The nucleotide sequences of adeR and adeS genes were assessed by PCR amplicon sequencing. To evaluate the association between reduced susceptibility to TGC and upregulation of AdeABC efflux pump, transcriptional level of adeB gene was quantified by RT-qPCR analysis. RESULTS: All 5 TGC-NSAB isolates had a TGC MIC of ≥4 mg/L and were resistant to all antimicrobials tested by disk diffusion method except for minocycline and doxycycline for which a susceptibility rate of 40% and 20% was observed, respectively. The tetX/X1 genes were not detected in any isolates. All TGC non-susceptible isolates harbored genetic alterations in the adeRS operon, including AdeS G186V, N268H, and D60N and AdeR A136V and V120I substitutions among, which G186V and D60N were predicted by PROVEAN tool analysis as inactivating alterations. Reduced TGC susceptibility was associated with upregulation of AdeABC efflux pump in all TGC non-susceptible isolates. CONCLUSION: It can be concluded from our results that reduced susceptibility to TGC in the studied isolates was mainly mediated by genetic alterations in the AdeRS system, which resulted in overexpression of AdeABC efflux pump. Emergence of TGC non-susceptibility among isolates that had not been previously exposed to TGC is an issue of great concern.

The association of Chlamydia pneumoniae infection with atherosclerosis: Review and update of in vitro and animal studies.

Previous studies have tended to relate Chlamydia pneumoniae (Cpn) infection to atherosclerosis. However, while serological studies have mostly reinforced this hypothesis, inconsistent and even contradictory findings have been reported in various researches. Recent papers have pointed to the significance of Cpn in atherosclerotic lesions, which are regarded as the initiator and cause of chronic inflammation. This bacterium develops atherosclerosis by phenotypic changes in vascular smooth muscle cells, dysregulation of endothelin-1 in the vascular wall, and releasing pro-inflammatory cytokines from Toll-like receptor-2 (TLR2). Furthermore, Cpn infection, particularly under hyperlipidemic conditions, enhances monocyte adhesion to endothelium; changes the physiology of the host, e.g., cholesterol homeostasis; and activates the Low-density lipoprotein (LDL) receptor, which is the initial step in atherogenesis. On the other hand, it has been reported that Cpn, even without the immune system of the host, has the ability to stimulate arterial thickening. Moreover, there is evidence that Cpn can increase the impact of the classical risk factors such as hyperlipidemia, pro-inflammatory cytokines, and smoking for atherosclerosis. Furthermore, animal studies have shown that Cpn infection can induce atherosclerotic, which alongside hyperlipidemia is a co-risk factor for cardiovascular disease. Although the exact link between Cpn and atherosclerosis has not been determined yet, previous studies have reported possible mechanisms of pathogenesis for this bacterium. Accordingly, investigating the exact role of this infection in causing atherosclerosis may be helpful in controlling the disease.

A closer look at pathogenesis of cerebral mucormycosis in diabetic condition: A mini review.

Patients with diabetes are considered a high-risk group involved with cerebral mucormycosis (CM). Due to the potential of Mucorales to invade sinuses and its rapid progression into orbit and retro-orbital areas and even brain, in most cases, CM is fatal in patients with diabetes. In the last few decades, mucormycosis and background conditions responsible for the development of its infections have received a great deal of attention. Dysfunction of innate and adaptive immune system, the increased amount of available nutrition, expression of host factors, and free iron level in plasma in diabetic ketoacidosis are among the topics that have been mostly taken into account so far. Therefore, it is important to clarify the molecular mechanisms that let the Mucorales to involve the patients with diabetes, which even at early stages of diagnosis and treatment, there is minimum chance to control the disease.

Helicobacter pylori Biofilm and New Strategies to Combat it.

Helicobacter pylori, the most frequent pathogen worldwide that colonizes around 50% of the world's population, causes important diseases such as gastric adenocarcinoma, chronic gastritis, and gastric mucosa-associated lymphoid tissue (MALT) lymphoma. In recent years, various studies have reported that H. pylori biofilm may be one of the critical barriers to the eradication of this bacterial infection. Biofilms inhibit the penetration of antibiotics, increase the expression of efflux pumps and mutations, multiple therapeutic failures, and chronic infections. Nanoparticles and natural products can demolish H. pylori biofilm by destroying the outer layers and inhibiting the initial binding of bacteria. Also, the use of combination therapies destroying extracellular polymeric substances decreases coccoid forms of bacteria and degrading polysaccharides in the outer matrix that lead to an increase in the permeability and performance of antibiotics. Different probiotics, antimicrobial peptides, chemical substances, and polysaccharides by inhibiting adhesion and colonization of H. pylori can prevent biofilm formation by this bacterium. Of note, many of the above are applicable to acidic pH and can be used to treat gastritis. Therefore, H. pylori biofilm may be one of the major causes of failure to eradication of infections caused by this bacterium, and antibiotics are not capable of destroying the biofilm. Thus, it is necessary to use new strategies to prevent recurrent and chronic infections by inhibiting biofilm formation.

Prevalence and molecular epidemiology of ceftaroline non-susceptible methicillin-resistant Staphylococcus aureus isolates, first clinical report from Iran.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the major pathogens in Iran with a high prevalence and a high level of antibiotic resistance. Ceftaroline is a fifth generation cephalosporin binding and inhibiting penicillin binding protein (PBP2a). METHODS: In the present study, 228 clinical MRSA isolates were collected from four cities of Iran and their susceptibility to ceftaroline was evaluated by E-test and the disk diffusion method. RESULTS: Our results showed a high susceptibility rate (97.3%) to ceftaroline in MRSA strains from Iran. Six isolates were found to be ceftaroline non-susceptible (CPT-NS) with Minimum inhibitory concentration (MIC) ≥2 µg/mL. All CPT-NS isolates were isolated from blood and tracheal aspirate and belonged to SCCmec type III as well as agr type I and were all susceptible to vancomycin. Out of six isolates, three, two and one belonged to spa type t030, t4864, and t969, respectively. Vancomycin, quinupristin/dalfopristin, linezolid, chloramphenicol, and tigecycline were the most active agents against CPT-NS isolates. CONCLUSION: Due to the broad-spectrum activity and low toxicity of ceftaroline as well as the increased rate of vancomycin resistance among MRSA strains in recent years, ceftaroline can be considered as a novel approach to treat MRSA-induced infections.

Bacteriophage therapy against Pseudomonas aeruginosa biofilms: a review.

Multi-Drug Resistant (MDR) Pseudomonas aeruginosa is one of the most important bacterial pathogens that causes infection with a high mortality rate due to resistance to different antibiotics. This bacterium prompts extensive tissue damage with varying factors of virulence, and its biofilm production causes chronic and antibiotic-resistant infections. Therefore, due to the non-applicability of antibiotics for the destruction of P. aeruginosa biofilm, alternative approaches have been considered by researchers, and phage therapy is one of these new therapeutic solutions. Bacteriophages can be used to eradicate P. aeruginosa biofilm by destroying the extracellular matrix, increasing the permeability of antibiotics into the inner layer of biofilm, and inhibiting its formation by stopping the quorum-sensing activity. Furthermore, the combined use of bacteriophages and other compounds with anti-biofilm properties such as nanoparticles, enzymes, and natural products can be of more interest because they invade the biofilm by various mechanisms and can be more effective than the one used alone. On the other hand, the use of bacteriophages for biofilm destruction has some limitations such as limited host range, high-density biofilm, sub-populate phage resistance in biofilm, and inhibition of phage infection via quorum sensing in biofilm. Therefore, in this review, we specifically discuss the use of phage therapy for inhibition of P. aeruginosa biofilm in clinical and in vitro studies to identify different aspects of this treatment for broader use.

Epidemiology, clinical features, diagnosis and treatment of cerebral mucormycosis in diabetic patients: A systematic review of case reports and case series.

BACKGROUND: Patients with diabetes are known as an important high-risk group for cerebral mucormycosis (CM). METHOD: We conducted a structured search using PubMed/MEDLINE to collect both case reports and case series case (ie including at least two patients) onto CM in diabetic patient published between 2000 and March 2020. RESULTS: Forty-five reports of individual cases and eighteen case series articles were included. India accounted for the largest share of reports with 37.7% and 38.8% of individual cases and case series, respectively. Mortality ranged from 0% to 100% in the case series. The overall mortality in the individual cases was 46.3%, and 64.2% of deaths were reported in patients with ketoacidosis diabetes. Facial swelling (53.3%), headache (44.4%), loss of vision (35.5%) and ophthalmoplegia (35.5%) were the most frequently reported clinical symptoms. In all patients except 4 (91.1%), CM was treated surgically; however, in many cases (42%), despite the use of surgery, death occurred. Amphotericin B deoxycholate (AMB) and lipid-based AMB (LAMB) were used as the first lines of treatment for all patients; however, posaconazole, echinocandins, hyperbaric oxygen therapy (HBOT) and deferasirox were used in combination for a number of patients. Posaconazole has been shown to have positive therapeutic effect; however, posaconazole, LAMB and HBOT are not commonly used in low-income and health-challenged countries. CONCLUSION: Cerebral mucormycosis is a rapidly progressive infection in diabetic patients and carries immense morbidity despite early diagnosis and treatment. Low-income countries have had the highest number of reports of the disease in recent years, indicating the need to control diabetes in these countries.