High frequency of carbapenemase in extensively drug-resistant Acinetobacter baumannii isolates in central Iran

OBJECTIVES

We assessed the frequency of occurrence for infections caused by wild-type A. baumannii, multidrug-resistant (MDR) or XDR A. baumannii, and CRAB. We detected different antibiotic resistance genes in the genomes of infectious A. baumannii strains from central Iran.

METHODS

This study investigated 546 clinical patient samples for the presence of A. baumannii by using conventional culture methods and PCR. Antibiotic resistance profiles, and the phenotypic and genotypic characteristics of various antibiotic genes were analyzed.

RESULTS

Out of 546 samples, 87 (15.9%) A. baumannii isolates were obtained using culture and all culture positive samples were also positive by PCR. The most effective antibiotics were polymyxin B (n = 84 strains) (96.6% susceptibility), colistin (n = 81) (93.1%), and ampicillin/sulbactam (n = 18) (20.7%). All clinical A. baumannii isolates were ESBL-positive. The number of CRAB was 84 (96.5%). All CRAB isolates were both MDR and XDR. Of all CRAB isolates, 78 out of 84 (92.4%) produced metallo-β-lactamase (MBL) by phenotypic diagnosis. The most abundant genes were blaPER (32/87; 36.7%), blaTEM (29/87; 33.3%), blaVEB (26/87; 29.8%) for ESBL and Ambler class D β -lactamases included blaOXA-23 (69/84; 82.1%), blaOXA-24 (46/84; 54.7%), MBLs included blaVIM (51/84; 60.7%), and blaIMP (28/84; 33.3%) for carbapenemase.

CONCLUSION

High frequencies of XDR A. baumannii and CRAB (96.5%) were detected in central Iran. Quick and accurate diagnosis, appropriate isolation of patients colonized or infected by CRAB isolates, application of accurate and effective infection control policies and programs, and appropriate preventive measures are deemed helpful in preventing the further spread of these resistant and clinically highly relevant strains.

High frequency of NDM-1 and OXA-48 carbapenemase genes among Klebsiella pneumoniae isolates in central Iran

BACKGROUND

The emergence and distribution of multidrug-resistant (MDR) and carbapenem-resistant Klebsiella pneumoniae (CRKP) has become a global health threat. Therefore, this study aimed to investigate the frequency and antibiotic resistance patterns of MDR, extensively drug-resistant (XDR), and CRKP, as well as the antibiotic resistance genes of Klebsiella pneumoniae (K. pneumoniae) isolates from patients' infectious samples from central Iran.

METHODS

This study examined 546 clinical samples of patients to identify K. pneumoniae. The isolates were investigated for their antibiotic resistance profile, extended-spectrum β-lactamase (ESBL), AMPC β-lactamase, carbapenemase resistance, sulfonamide, tetracycline, plasmid-mediated quinolone resistance (PMQR) along with their resistance genes, integrase, and quaternary ammonium compounds (qac) by polymerase chain reaction (PCR).

RESULTS

Out of 546 clinical samples, 121 (22.1%) cases of K. pneumoniae were identified using culture and PCR methods. The highest antibiotic resistance rates were found for ampicillin (119/121; 98.3%), cotrimoxazole (78/121; 64.4%), and cefixime, cefotaxime, ceftriaxone, and ceftazidime as a group (77/121; 63.6%). Tigecycline, colistin, and fosfomycin were the most effective antimicrobial agents with 98.4%, 96.7%, and 95.9% susceptibility, respectively. The amount of CRKP was 51 (42.1%). All CRKP isolates were MDR. The most abundant genes were bla_TEM (77/77; 100%), bla_CTX-M1 (76/77; 98.7%), bla_SHV (76/77; 98.7%), bla_CTX-M15 (73/77; 94.8%) for ESBL; bla_CIT 28 (48.3%) and bla_CMY-2 26 (44.8%) for AMPC β-lactamase; and bla_OXA-48 46 (90.1%) and bla_NDM 36 (70.5%) for carbapenemase. Among the PMQR determinants, qnrB (25/52; 48%), qnrS (19/52; 36.5%), and qnrA (11/52; 21.1%) were positive from the isolates. TetA and tetB were recognized in 25 (44.6%) and 17 (30.3%) isolates, respectively. Class 1 and 2 integrons were recognized in 97 (80.1%) and 53 (43.8%) isolates, respectively.

CONCLUSIONS

Due to the high prevalence of MDR and CRKP in central Iran, tracking and immediate intervention are necessary for control and inhibition of K. pneumoniae resistant isolates. Tigecycline, colistin, and fosfomycin are the best treatment options for treatment of patients with CRKP in this geographical area.

In vivo efficiency of the produced recombinant lysostaphin antimicrobial peptide in treatment of methicillin-resistant Staphylococcus aureus (MRSA) skin infection in a mouse model

Background and Objectives

Staphylococcus simulans secretes an antimicrobial compound called lysostaphin, which has bactericidal properties. It destroys staphylococci through the hydrolysis of peptidoglycan in the cell wall. Therefore, this unique property indicates the high ability of lysostaphin in the treatment of staphylococcal infections and is considered as an anti-staphylococcal agent.

Materials and Methods

Escherichia coli BL21 (DE3) competent cells were transformed with pET32a-lysostaphin clone and induced by isopropyl-β-D-thio-galactoside (IPTG). The recombinant protein was purified by affinity chromatography. Recombinant lysostaphin -A-based ointment was used for external wound healing in animal model. In vivo activity of ointment was evaluated by clinical evidences and cytological microscopic assessment.

Results

Our results showed the recombinant protein was produced exactly. The results of checkerboard tests showed MIC, MBC and antibacterial activity test an acute reduction of cell viability during the use of lysostaphin, and SEM results approved the intense wrecking effects of lysostaphin in combination on bacterial cells. Macroscopic findings and microscopic data showed that the recombinant lysostaphin ointment was effective on excisional wound healing.

Conclusion

Our findings proved that the recombinant lysostaphin ointment was effective on wound healing due to Staphylococcus aureus infection.

The significant role of Carbapenems-resistant Acinetobacter Baumannii in mortality rate of patients with COVID-19

Background: Infections caused by Acinetobacter baumannii, especially carbapenem-resistant (CR) strains, pose important challenges in patients with COVID-19 infection. Therefore, in the present study, we investigated co-infection and antimicrobial resistance patterns, as well as the role of A. baumannii in the outcome of patients with COVID-19. Materials and methods: Between February 2019 and January 2021, 141 patients with A. baumannii infections were detected from seven different hospitals (A to G) in Arak, Iran, and the antibacterial susceptibility pattern of these isolates was evaluated using disk diffusion and E-test methods. Forty-seven of these patients were co-infected with COVID-19. During the study, the data about the clinical course, demographic data, and the role of A. baumannii infections in the mortality rate of COVID-19 patients were collected. Results: Hospitals A and B reported the most patients, with 53 (38%) and 47 (33%), respectively. Additionally, most cases (105 cases, 75%) were reported from surgical and general ICUs. Mechanical ventilators were detected as predisposing factors in 95 (67%) patients, and infection was detected in 20% of patients on the 10th day after intubation. All of the A. baumannii isolates were resistant to different classes of antibiotics, such as carbapenems. Notably, 33% (47 patients) were also positive for COVID-19, and 68% (32 patients) died due to the infection. Statistical analysis showed a significant role of A. baumannii co-infection in the mortality rate of COVID-19 patients (p-value 0.05). Conclusion: co-infection with A. baumannii is one of the most important challenges in COVID-19 patients. Our results showed that all isolated bacteria were CR and significantly increased mortality rates in COVID-19 patients.

The LL-37 Antimicrobial Peptide as a Treatment for Systematic Infection of Acinetobacter baumannii in a Mouse Model

BACKGROUND

The antimicrobial peptides (AMPs) played a critical role in the innate immunity of the host and are considered natural sources illustrating a broad-spectrum antimicrobial activity with high specificity and low cytotoxicity. AMPs generally possess a net positive charge and have amphipathic structures. Thus, AMPs can bind and interact with negatively charged bacterial cell membranes, leading to destructive defects in biomembranes and ending in cell death. LL37 is the only human cathelicidin-derived antimicrobial peptide that shows a broad spectrum of antimicrobial activity.

MATERIALS AND METHODS

To determine the antibacterial efficiency of LL37 in a mouse model of systemic A. baumannii infection, LL37 corresponding gene was expressed in E. coli, purification and refolding situations were optimized. The antimicrobial performance of produced LL-37 against A. baumannii was evaluated in vitro via MIC and Time Kill assays, and its destructive effects on the bacterial cell were confirmed by SEM image.

RESULTS

The recombinant LL37 showed strong antibacterial function against A. baumannii at 1.5 μg/mL concentration. Time kill assay showed a sharp reduction of cell viability during the first period of exposure, and complete cell death was recorded after 40 min exposure.

CONCLUSION

Furthermore, in vivo results represented a significant ability of LL37 in the treatment of systematic infected mouse models, and all infected mice receiving LL37 protein survived without no trace of bacteria in their blood samples.

The importance of using routine laboratory tests in the diagnosis and prognosis of patients with coronavirus disease 2019: Shedding light on clinical laboratory data in COVID-19

BACKGROUND

Novel coronavirus (COVID-19) pandemic has become a global concern and requires early detection, isolation, and treatment. Our purpose is to find some beneficial information by analyzing the COVID-19 laboratory data to provide guidance for clinical practice.

MATERIAL AND METHODS

In this study, 174 patients with confirmed COVID-19 infection were admitted. We evaluated the hematological and biochemical parameters in these patients and in 80 healthy individuals.

RESULTS

We found that there was significant difference between WBC, LYM, RBC, HB, and HCT parameters of patients and healthy counterparts (p < .001), though there was no remarkable change between NEU, MONO, PLT, and other characteristics of RBC values of patients and the control group (p ≥ .09). Among the evaluated biochemical parameters, the values of CK-MB and LDH in the patient group were significantly different from the control group (p < .01), while other biochemical indicators were in the normal range.

CONCLUSION

Several hematological and biochemistry parameters, in particular WBC, LYM, RBC, HB, HCT, CK-MB, and LDH, could be beneficial supplementary approach for COVID-19 infection evaluation to confirm risk stratification and effective management.

Common Etiological Agents in Adult Patients with Gastroenteritis from Central Iran

Aims: This study represents the first analysis from Iran for both the frequency of the most common causes of infectious diarrhoea and their antibiotic resistance patterns in adult patients. Methods: Adult stool specimens (n = 211) were analyzed. Stool specimens were analyzed using standard microbiological, polymerase chain reaction, and reverse transcription polymerase chain reaction tests to identify bacterial, parasitic, and viral enteropathogens. Antibiotic resistance profiles were determined. Results: Enteropathogens were identified in 46.4% (98/211) of the surveyed samples. This included 33.1% (70/211) bacterial infections, including 9.9% (21/211) diarrheagenic Escherichia coli (DEC) and 8.5% (18/211) Shigella spp. We detected 7.1% (15/211) parasitic infections (mostly Giardia lamblia) and 6.1% (13/211) viral infections (mostly adenovirus). The DEC and Shigella spp. isolates included many multi-drug resistant (MDR) isolates (95.2% and 77.7%, respectively), and extended spectrum-β-lactamase (ESBL) genes were often present (57.1% and 61.1%, respectively). The most commonly identified ESBL genes in the DEC and Shigella spp. isolates were bla_TEM (100% in both species), bla_CTX-M15 (91.6% and 100%, respectively), AmpC bla_CIT (80% and 100%, respectively), and bla_DHA (80% and 100%, respectively). Conclusions: Bacterial infection was the primary cause of infectious diarrhea, affecting one-third of the adults. The frequency of DEC and Shigella spp. was higher than for other enteropathogens. The high prevalence of MDR, the elevated incidence of ESBL genes among Shigella spp. and DEC isolates, and the presence of quinolone resistance in the Salmonella spp. isolates represent a significant challenge for gastroenteritis diagnosis and treatment in this region.

PLGA-Based Nanoplatforms in Drug Delivery for Inhibition and Destruction of Microbial Biofilm

The biofilm community of microorganisms has been identified as the dominant mode of microbial growth in nature and a common characteristic of different microorganisms such as Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis. The biofilm structure helps in the protection from environmental threats including host immune system and antimicrobial agents. Thus, the biofilm community has led to a higher prevalence of multidrug-resistant (MDR) strains in recent years. In this regard, the use of a new class of antibiotics, natural compounds, and anti-biofilm enzymes has been considered for the destruction of the microbial biofilm. However, different drawbacks such as low penetration, high susceptibility to degradation, instability, and poor solubility in aqueous solutions limit the use of anti-biofilm agents (ABAs) in a clinical setting. As such, recent studies have been using poly lactic-co-glycolic acid (PLGA)-based nanoplatforms (PLGA NPFs) for delivery of ABAs that have reported promising results. These particles, due to proper drug loading and release kinetics, could suppress microbial attachment, colonization, and biofilm formation for a long time. Additionally, PLGA NPFs, because of the high drug-loading efficiencies, hydrophilic surface, negative charge, and electrostatic interaction, lead to effective penetration of antibiotics to the deeper layer of the biofilm, thereby eliminating the microbial biofilm. Thus, PLGA NPFs could be considered as a potential candidate for coating catheters and other medical material surfaces for inhibition and destruction of the microbial biofilm. However, the exact interaction of PLGA NPFs and the microbial biofilm should be evaluated in animal studies. Additionally, a future goal will be to develop PLGA formulations as systems that can be used for the treatment of the MDR microbial biofilm, since the exact interactions of PLGA NPFs and these biofilm structures are not elucidated. In the present review article, we have discussed various aspects of PLGA usage for inhibition and destruction of the microbial biofilm along with different methods and procedures that have been used for improving PLGA NPF efficacy against the microbial biofilm.

Isolation of a lytic bacteriophage against extensively drug-resistant Acinetobacter baumannii infections and its dramatic effect in rat model of burn infection

Objectives

Acinetobacter Baumannii is an opportunistic nosocomial pathogen belonging to the Moraxellaceae family. The emergence of multidrug resistant strains of this pathogen caused many problems for hospitals and patients. The aim of the current study was to isolate, identify, and morphologically, physiologically, and in vivo analyze a new lytic bacteriophage targeting extensively drug‐resistant (XDR) A. baumannii.

Materials and Methods

Different wastewater samples were tested for isolation of lytic bacteriophage against 19 A. baumannii isolates obtained from patients hospitalized in a hospital in Arak, Iran, from January 2019 to March 2019. The phenotypic and genotypic characteristics of A. baumannii strains (resistance genes including: adeA, adeB, adeC, adeR, adeS, ISAba1, blaOXA‐23, blaOXA‐24) were analyzed. The isolated phage characteristics including adsorption time, pH and thermal stability, host range, one‐step growth rate, electron microscopy examination, and therapeutic efficacy of the phage were also investigated. Therapeutic efficacy of the phage was evaluated in a rat model with burn infection of XDR A. baumannii. The lesion image was taken on different days after burning and infection induction and was compared with phage untreated lesions.

Results

The results showed unique characteristics of the isolated phage (vB‐AbauM‐Arak1) including high specificity for Acinetobacter baumannii, stability at a relatively wide range of temperatures and pH values, short adsorption time, short latent period, and large burst size. In relation to the therapeutic efficacy of the phage, the lesion area decreased in phage‐treated groups over 14 days than in those untreated, significantly (p < 0.05).

Conclusion

Our findings demonstrated that isolated lytic phage was able to eliminate burn infections caused by XDR A. baumannii in a rat model. So, it may be recommended as alternative options toward to developing a treatment for extensively drug resistant Acinetobacter infections.

Ib-AMP4 antimicrobial peptide as a treatment for skin and systematic infection of methicillin-resistant Staphylococcus aureus (MRSA)

OBJECTIVES

Antimicrobial peptide compounds (AMPs) play important roles in the immune system. They also exhibit significant anti-tumor and antibacterial properties. Most AMPs are cationic and are able to bind bacterial cell membranes through electrostatic affinity. Ib-AMP4 is a plant-derived AMP that exerts rapid bactericidal functions. In the present study, the antibacterial efficiency of the produced recombinant Ib-AMP4 in elimination of Methicillin-resistant Staphylococcus aureus (MRSA) bacterial infection, was investigated under in vitro and in vivo situations.

MATERIALS AND METHODS

The synthesized Escherichia coli codon-optimized gene sequences of the Ib-AMP4 were expressed in E. coli BL21 (DE3) pLysS. The recombinant Ib-AMP4 was purified and refolding conditions were optimized. The antibacterial efficiency of the refolded peptide against MRSA was tested under in vivo and in vitro situations for treatment of skin and systematic infection of MRSA in a mouse model.

RESULTS

Antibacterial assays confirmed the antibacterial function of Ib-AMP4 against MRSA. SEM results proved the destructive effects of applying Ib-AMP4 on MRSA biomembrane. Time-kill curve and growth kinetic assay illustrated rapid antibacterial activity of the produced Ib-AMP4. Moreover, Ib-AMP4 showed significant infection treatment ability in a mouse model and all infected mice receiving Ib-AMP4 protein survived and there was no trace of bacteria in their blood samples.

CONCLUSION

The results confirmed the rapid antibacterial potential of the produced recombinant Ib-AMP4 to be used for efficient treatment of MRSA infection.

Comparison of three interventional approaches to prevent ventilator-associated pneumonia in intensive care units (ICUs): A clinical trial study

Background: Ventilator-associated pneumonia (VAP) is an infectious pulmonary disease that develops after 48 hours of ventilation. To date, several methods have been proposed to reduce VAP occurrence, such as the VAP prevention bundle, which involves raising the head of the bed, reducing sedation, avoiding deep vein thrombosis, and preventing peptic ulcer in the gastrointestinal system. The purpose of this study was to evaluate the role of personnel in hand washing, case airway suctioning, and systematic monitoring in the prevention of VAP.

Methods: In the current clinical trial, 129 patients hospitalized and intubated at Vali-e-Asr Hospital ICU in Arak, Iran, were included in the study and randomized to one of the three VAP prevention methods: group A, VAP prevention bundle measures; group B, group A measures plus washing of patients’ mouth with 0.12% chlorhexidine and suction of secretion every six hours; and finally group C, group B measures plus 72-hour suction package. Demographic information, VAP diagnosis, and outcome of each patient were recorded in the special checklist.

Results: The age of the patients ranged from 18 years to 93 years with a mean of 54.6 ± 21.8 years. There was no significant difference in age, sex, Clinical Pulmonary Infection Score (CPIS), and Glasgow Coma Scale (GCS) between the three groups. However, there is a significant relationship between chest X-ray (CXR) index and pneumonia in the three groups (p < 0.05). The prevalence of pneumonia is generally seen to be higher in patients who were local, diffuse, or patchy than those who had no infiltration (p < 0.05).

Conclusion: This study showed that the application of VAP prevention bundle measures, mouthwash with chlorhexidine, personnel hand washing, airway suctioning, and systematic monitoring is an efficient approach to the prevention of VAP in ICUs.

Association between colorectal cancer and Fusobacterium nucleatum and Bacteroides fragilis bacteria in Iranian patients: a preliminary study

Background and aim

Recent studies have proposed that commensal bacteria might be involved in the development and progression of gastrointestinal disorders such as colorectal cancer (CRC). Therefore, in this study, the relative abundance of Fusobacterium nucleatum, Bacteroides fragilis, Streptococcus bovis/gallolyticus, and Enteropathogenic Escherichia coli (EPEC) in CRC tissues, and their association with clinicopathologic characteristics of CRC was investigated in Iranian patients. Moreover, the role of these bacteria in the CRC-associated mutations including PIK3CA, KRAS, and BRAF was studied.

Method

To these ends, the noted bacteria were quantified in paired tumors and normal tissue specimens of 30 CRC patients, by TaqMan quantitative Real-Time Polymerase Chain Reaction (qPCR). Next, possible correlations between clinicopathologic factors and mutations in PIK3CA, KRAS, and BRAF genes were analyzed.

Results

In studied samples, B. fragilis was the most abundant bacteria that was detected in 66 and 60% of paired tumor and normal samples, respectively. Furthermore, 15% of the B. fragilis-positive patients were infected with Enterotoxigenic B. fragilis (ETBF) in both adenocarcinoma and matched adjacent normal samples. F. nucleatum was also identified in 23% of tumors and 13% of adjacent normal tissue samples. Moreover, the relative abundance of these bacteria determined by 2^-ΔCT was significantly higher in CRC samples than in adjacent normal mucosa (p < 0.05). On the other hand, our findings indicated that S. gallolyticus and EPEC, compared to adjacent normal mucosa, were not prevalent in CRC tissues. Finally, our results revealed a correlation between F. nucleatum-positive patients and the KRAS mutation (p = 0.02), while analyses did not show any association between bacteria and mutation in PIK3CA and BRAF genes.

Conclusion

The present study is the first report on the analysis of different bacteria in CRC tissue samples of Iranian patients. Our findings revealed that F. nucleatum and B. fragilis might be linked to CRC. However, any link between gut microbiome dysbiosis and CRC remains unknown.

Investigation into antibacterial and wound healing properties of platelets lysate against Acinetobacter baumannii and Klebsiella pneumoniae burn wound infections

Background and aim

Treatment of burn wound infections has become a global challenge due to the spread of multidrug-resistant bacteria; therefore, the development of new treatment options for the mentioned infections is essential. Platelets have drawn much attention for this purpose because they are a safe and cost-effective source of different antimicrobial peptides and growth factors. The present study evaluated antibacterial effects and wound healing properties of Platelet-derived Biomaterial (PdB) against Acinetobacter baumannii and Klebsiella pneumoniae burn wound infections.

Methods

PdB was prepared through the freezing and thawing process and then, in vitro antibacterial effect was determined by disk diffusion and broth microdilution methods. Afterward, burn wound was inflicted on 56 rats, infected with both bacteria, and topical administration was performed to evaluate antibacterial effects and wound healing properties of PdB.

Results

In vitro results showed that PdB inhibited the growth of A. baumannii in the highest dose (0.5), while we did not detect any inhibitory effects against K. pneumoniae. By contrast, PdB significantly inhibited the growth of bacteria in treated animal wounds compared to the control groups (P value < 0.05). Macroscopic assessments pointed to the significant enhancement of wound closure in the treated animals. In addition, histopathological examination demonstrated that treatment of rats with PdB led to a considerable increase in re-epithelialization and attenuated the formation of granulation tissue (P value < 0.05).

Conclusion

The use of topical PdB is an attractive strategy for treating A. baumannii and K. pneumoniae burn wound infections because it inhibits bacterial growth and promotes wound healing properties.

Quinolone resistant Salmonella species isolated from pediatric patients with diarrhea in central Iran

Background

This study aimed to investigate the frequency and the antibiotic resistance patterns of Salmonella species that were isolated from infectious diarrhea samples taken from pediatric patients in central Iran.

Methods

The study analyzed 230 stool specimens that were cultured on XLD, MacConkey agar and GN broth. Polymerase chain reaction (PCR) assay was used to identify the Salmonella genus. The antibiotic resistance profiles and the frequency of quinolone and integron genes were obtained.

Results

Out of 230 samples of infectious diarrhea, 21 (9.1%) cases of Salmonella spp. were identified using culture methods. Another 28 (12.1%) samples had positive PCR results, with S. serovar Paratyphi B and C (9/21; 42.8%) and S. Typhi (3/21; 14.3%) being the most recognized. The highest antibiotic resistance rates were found for nalidixic acid (15/21; 71.4%), tetracycline (9/21; 42.8%). However, six (28.5%) of isolates were found resistant to cotrimoxazole, ampicillin and chloramphenicol. Among the plasmid-mediated quinolone resistance (PMQR) determinants, qnrS, qnrA, and qnrB were positive in (9/15; 60%), (6/15; 40%) and (3/15; 20%) of the isolates, respectively. Class 1 and 2 integrons were identified in 15 (71.4%) and 3 (14.3%) isolates, respectively.

Conclusion

High rates of quinolone resistant and low frequency of MDR Salmonella spp. isolates were identified in central Iran, similar to findings in other parts of Asia. To prevent the spread of these resistant strains, the antimicrobial resistance of Salmonella spp. isolates should be under constant surveillance, and empiric antibiotic therapy should be adapted appropriately.

Contribution value of coagulation abnormalities in COVID-19 prognosis: a bright perspective on the laboratory pattern of patients with coronavirus disease 2019

OBJECTIVE

From the beginning of the novel coronavirus infection (COVID-19) pandemic in the world, much efforts have been accomplished to explain a precise clinical feature for the disease and to find the best therapeutic approach for the patients. Although coagulation abnormalities have found in novel coronavirus infection (COVID-19) patients, still little is known about the association between the disease and changes in coagulation parameters. Our purpose is to evaluate the differences between the coagulation parameters between COVID-19 patients and healthy counterparts.

PATIENTS AND METHODS

63 patients with confirmed COVID-19 infection were admitted to the present study. We evaluated coagulation value in these patients and in 40 healthy individuals.

RESULTS

We found that although there was no significant difference between PT and PTT values in patients and healthy counterparts, the fibrinogen values in patients were higher than the control group (p < 0.05). Moreover, the values of fibrin/fibrinogen degradation products (FDP) and D-dimer in all COVID-19 cases were considerably higher than those in control people (p < 0.05). Of note, FDP and D-dimer in patients with regular COVID-19 infection were lower than patients with severe forms.

CONCLUSIONS

It seems that the conduction of routine blood coagulation test could be a beneficial supplementary approach for early diagnosis of COVID-19. In addition, our study shed more light on the therapeutic value of anti-coagulant-based treatment for COVID-19 patients, especially for those with severe type of the disease.

Wound healing performance of PCL/chitosan based electrospun nanofiber electrosprayed with curcumin loaded chitosan nanoparticles

In this study, the electrospun poly(ε-caprolactone) (PCL)/Chitosan (CS)/curcumin (CUR) nanofiber was fabricated successfully with curcumin loaded chitosan nano-encapsulated particles (CURCSNPs). The morphology of the produced CURCSNPs, PCL, PCL/CS, PCL/CS/CUR, and PCL/CS/CUR electrosprayed with CURCSNPs were analyzed by scanning electron microscopy (SEM). The physicochemical properties and biological characteristics of fabricated nanofibers such as antibacterial, antioxidant, cell viability, and in vivo wound healing efficiency and histological assay were tested. The electrospraying of CURCSNPs on surface PCL/CS/CUR nanofiber resulted in the enhanced antibacterial, antioxidant, cell proliferation efficiencies and higher swelling and water vapor transition rates. In vivo examination and Histological analysis showed PCL/CS/CUR electrosprayed with CURCSNPs led to significant improvement of complete well-organized wound healing process in MRSA infected wounds. These results suggest that the application of PCL/CS/CUR electrosprayed with CURCSNPs as a wound dressing significantly facilitates wound healing with notable antibacterial, antioxidant, and cell proliferation properties.

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.

Multi-Drug-Resistant Diarrheagenic Escherichia coli Pathotypes in Pediatric Patients with Gastroenteritis from Central Iran

Background

Diarrheagenic Escherichia coli (DEC) is a significant cause of gastroenteritis and a major public health problem. This study investigates the prevalence and the antibiotic resistance patterns of DEC that were isolated from infectious diarrhea samples of pediatric patients from central Iran.

Patients and Methods

Pediatric diarrhea samples were collected from 230 pediatric patients visiting the hospital. E. coli pathotypes were diagnosed by using conventional culture methods and PCR. Antibiotic resistance profiles, the frequency of multi-drug resistance (MDR), and the phenotypic and genotypic characteristics of extended spectrum-β-lactamase (ESBL), AmpC and integron-associated genes were analyzed.

Results

Of the 230 samples of infectious diarrhea, 91 (39.5%) produced E. coli isolates. Of these, 32 cases (35.1%) were identified as DEC by culture and PCR. The frequency of the E. coli pathotypes obtained was as follows: EAEC 11/32 (34.3%), EPEC 9/32 (28.1%), ETEC 6/32 (18.7%), EIEC 3/32 (9.3%), and EHEC 3/32 (9.3%). The antibiotic resistance rates were greater for nalidixic acid (30/32; 93.7%), ampicillin (29/32; 90.6%), and tetracycline (25/32; 78.1%) than for any of the other tested antibiotics. High levels of MDR (25/32; 78.1%) and the presence of ESBL (18/32; 56.2%) and AmpC (9/32; 28.1%) were observed in the DEC isolates. The isolates showed a higher frequency of the ESBL genes [bla_TEM (18/18; 100%), bla_CTX-M15 (17/18; 94.4%)], and AmpC [bla _CIT (4/9; 44.4%) and bla_DHA (4/9; 44.4%)] than of the other ESBL and AmpC genes.

Conclusion

Compared to the previous study, DEC appeared to be the second-most abundant agent of diarrhea in pediatric patients after Campylobacter jejuni, with frequent MDR and ESBL presence.

The Frequency of the Intestinal Parasites Giardia Lamblia and Entamoeba Histolytica in Pediatric Diarrhea Specimens from Central Iran

Introduction:

Intestinal parasitic infections, particularly those caused by Giardia lamblia, are among the major health problems that exist worldwide, especially in developing countries. This study aimed to investigate the prevalence of the intestinal parasites Giardia lamblia and Entamoeba histolytica that were isolated from samples of infectious diarrhea in pediatric patients from Central Iran.

Methods:

This descriptive cross-sectional study included 230 samples of infectious diarrhea that were collected from May 2015 to February 2016. Direct observation, the formalin-ether sedimentation method and the technique using the Polymerase Chain Reaction (PCR) of β-giardin and EH primers were used for the identification of Giardia lamblia and Entamoeba histolytica.

Results:

Out of 230 samples of infectious diarrhea, five cases (2.1%) of Giardia lamblia and no cases (0%) of Entamoeba histolytica were identified using the formalin-ether sedimentation method and the same result were obtained using PCR technique. Of the five patients who had Giardia lamblia, three (60%) were male and two (40%) were female. The most common clinical symptoms in these patients were stomach ache and diarrhea (100%) and mucus in the stool (80%).

Conclusion:

Giardia lamblia was introduced as a parasitic agent causing diarrhea from Central Iran. The results indicate that pediatricians and, even more importantly, experts in laboratories should pay special attention to the identification of this parasite to treat the patients as effectively and as quickly as possible.

Elimination of Staphylococcus aureus nasal carriage in intensive care patients lowers infection rates

This study surveys the clinical relevance of the nasal Staphylococcus aureus colonization status on intensive care unit (ICU)-acquired S. aureus infections and compares molecular characteristics of isolates from the nose and infectious sites. The 390 patients included comprised 278 non-carriers and 112 carriers. Among the carriers, 56 were decolonized with mupirocin. Decolonization was verified through a second (negative) culture. Spa typing and virulence gene profiling were performed for all isolates. Twenty six S. aureus infections were detected in the carriage group and 20 in the non-carriage group. Eighteen of these 26 (69.2%) infections were among carriers, and 8 of these 26 (30.8%) infections occurred among decolonized carriers (p = 0.02). Overall, 31/112 (27.7%) of the colonized patients and 25/46 (60.1%) of infection were due to methicillin-resistant S. aureus (MRSA). The highest frequency virulence genes were sea and hlg (both 100%) in nasal isolates and sea, hlg, fnb, and clf (100%) for infectious isolates. t030 was the most abundant spa type overall. S. aureus carriers were more likely to develop S. aureus infection compared with decolonized and non-carrying patients. The sources of ICU S. aureus infection appear to be exogenous mostly, and a predominant clone (spa type 030) plays an important role. We confirm that nasal mupirocin treatment prevents ICU infections even when there is an increased prevalence of nosocomial MRSA.

Frequency of Listeria monocytogenes Isolated from Diarrhea Samples of Pediatric Patients at Central Iran

BACKGROUND

Listeria monocytogenes is a primarily foodborne bacterial pathogen that is one of the causative agents of gastroenteritis. However, the prevalence of L. monocytogenes infection in pediatric patients with diarrheal disease is not clearly identified in the Iranian population. This study aimed to investigate the frequency of L. monocytogenes isolates found in infectious diarrhea samples of pediatric patients in an Iranian population.

METHODS

A total of 173 infectious diarrhea samples collected from pediatric patients were used in this crosssectional study. Samples were collected from patients referred to the Children's Educational-Therapeutic Center affiliated with the Arak University of Medical Sciences in Arak, Iran from May-September 2015. To identify the presence of L. monocytogenes, the samples were directly inoculated into the Listeria Enrichment Broth Base through cold enrichment, then plated onto isolated exclusive Listeria Selective Agar Base. As an alternative method for identifying L, monocytogenes, Polymerase Chain Reaction (PCR) of the InlA gene was used.

RESULTS

Of the 173 infectious diarrhea samples, eight (4.6%) with L. monocytogenes were identified using exclusive culture media, while nine (5.2%) were identified using PCR. The majority of L. monocytogenes infections (seven cases (77.7%)) were observed in children under the age of five.

CONCLUSION

Our results show L. monocytogenes infections to have a low prevalence for causing diarrhea in children in the central region of Iran. This should be taken into consideration by pediatricians when treating intestinal diseases.

Multidrug-resistant Shigella infection in pediatric patients with diarrhea from central Iran

Background:Shigella spp. are primary pathogens of diarrhea in children worldwide. Emergence of resistance to fluoroquinolones and third-generation cephalosporins is crucial in the management of pediatric shigellosis. We determined the prevalence and the antibiotic resistance patterns of Shigella species isolated from pediatric patients in central Iran.

Materials and methods: Pediatric diarrhea samples (n=230) were cultured on MacConkey and XLD agar media and in GN broth. Genus-specific PCR for ipaH was also used for detection directly from fecal specimens. Antibiotic resistance and the frequency of ESBL and AmpC genes were determined.

Results: Out of the 230 samples, 19 (8.2%) cases of Shigella spp. were identified using culture. Twenty-six samples were positive by PCR (11.3%), S. flexneri (4/19; 21%) and S. sonnei (15/19; 78.9%) being the most detected. The highest antibiotic resistance rates were found for cotrimoxazole (19/19; 100%), ampicillin (16/19; 84.2%), cefixime (13/19; 68.4%) and ceftriaxone (12/19; 63.1%). Ten cases showed phenotypic ESBL presence and all these strains were positive for bla_TEM, bla_CTX-M-1, and bla_CTX-M-15. Three strains were AmpC positive, all of which harbored bla_CMY-2 and two contained bla_CIT. Of the 19 Shigella isolates 5 (26.3%), 2 (10.5%), and 1 (5.2%) were phenotypically resistant to nalidixic acid, ciprofloxacin, and norfloxacin, respectively. Class 1 integron was found in 18 (94.7%) isolates whereas class 2 integron was found in 19 (100%) strains.

Conclusion: We found a considerable presence of Shigella species with elevated antibiotic resistance levels. In particular, the resistance to third-generation cephalosporins (ESBL) and ciprofloxacin must be taken seriously.

Quinolone and Macrolide-Resistant Campylobacter jejuni in Pediatric Gastroenteritis Patients from Central Iran

Aims: To determine the prevalence and the antibiotic resistance patterns of Campylobacter jejuni isolated from pediatric diarrhea patients in central Iran. Materials and Methods: Stool specimens (n = 230) were investigated using a modified Gram stain, two specific culture media, and C. jejuni-specific PCR. Antibiotic resistance profiles and relevant resistance genes were determined. Genetic relationships among a selection of the isolates were studied by Fla typing. Results: Out of the 230 diarrhea samples, 48 (20.8%) cases of C. jejuni were identified using modified Gram stain, 45 (19.5%) using the culture media, and 76 (33%) cases were identified using PCR. The highest antibiotic resistance rates were observed in 37 (82.2%) strains against tetracycline, in 32 (71.1%) against ciprofloxacin, and in 31 (68.8%) against erythromycin. Twenty (44.4%) isolates were resistant to ciprofloxacin and erythromycin simultaneously. Genotypic investigations found 36 (97.3%) strains carrying the tet (o) gene, 31 (96.8%) harboring the cmeB gene, 22 (68.7%) strains with the gyrA6 gene, 20 (64.5%) strains containing a 23S rRNA mutation, and 21 (65.6%) strains with the qnrS gene. Fla typing of a random subset of 14 strains revealed 11 different types showing the genomic diversity of the isolates. Strains sharing the same Fla type could be easily distinguished by their resistance gene profile. Conclusions: This is the first study to demonstrate that genetically diverse quinolone-macrolide-resistant C. jejuni is an important cause of gastroenteritis in children from central Iran. Pediatricians should consider these resistance features once the antibiotic prescription is necessary for prevention of possible complications, especially in those under 5 years of age. Of note, most cases of Campylobacter diarrhea are self-limiting and antibiotics should only be prescribed in those cases where severe complications evolve.

Bioactive 2-(Methyldithio)Pyridine-3-Carbonitrile from Persian Shallot (Allium stipitatum Regel.) Exerts Broad-Spectrum Antimicrobial Activity

Antibiotic resistance is a problem that continues to challenge the healthcare sector, especially in clinically significant pathogens like methicillin-resistant Staphylococcus aureus (MRSA). Herein is described the isolation and structure elucidation of a bioactive compound from Allium stipitatum with antimicrobial activity. Crude Allium stipitatum dichloromethane extract (ASDE) was subjected to systematic purification by chromatographic procedures to afford various bioactive fractions. A fraction that exhibited anti-MRSA activity (4 µg·mL-1) was further characterized to determine the structure. The structure of the compound was elucidated as 2-(methyldithio)pyridine-3-carbonitrile (2-Medpy-3-CN). The 2-Medpy-3-CN compound, which was screened for antimicrobial activity, exhibited minimum inhibitory concentrations (MICs) in the range of 0.5 to >64 µg·mL-1 for tested bacterial species and 0.25 to 2 µg·mL-1 for Candida spp. Further studies are important to confirm the drug target and mechanism of action.

Staphylococcus aureus Colonization in Patients Undergoing Total Hip or Knee Arthroplasty and Cost-effectiveness of Decolonization Programme

BACKGROUND

Periprosthetic joint infection is a devastating complication of total joint arthroplasty. It seems that the patient's skin, nose, throat, and urine are important sites for microbial colonization. Colonization with staphylococcus aureus, especially methicillin resistant increases the risk of periprosthetic joint infection. The aim of this study was to assess the prevalence of staphylococcus aureus colonization in patients candidate for arthroplasty in central Iran as well as cost-effectiveness of decolonization program for prevention of post-arthroplasty infection.

METHODS

A total of 226 patient candidates for total joint arthroplasty were enrolled in this prospective cross-sectional study between January 2014 and January 2016. Specimens from nose, throat, groin skin, and urine were sent for bacteriologic culture and sensitivity test. Analysis cost-effectiveness was then performed for decolonization programme.

RESULTS

Patients had positive cultures from nose (15.9%), throat (4.4%), groin skin (3.1%), and urine (0.9%). In general, 20.8% of the patients had positive cultures for staphylococcus aureus, among whom, 1.8% were methicillin resistant. Based on cost-effectiveness analysis, decolonization program leads to 80% reduction in costs.

CONCLUSION

According to our results, although colonization with methicillin sensitive staphylococcus aureus in patients undergoing hip or knee arthroplasty is lower than other studies but colonization with methicillin resistant staphylococcus aureus is similar to others. Also, decolonization programme in these patients was found to be very cost-effective.

LEVEL OF EVIDENCE

II.

Antibacterial and Antibiofilm Activities of Nonpolar Extracts of Allium stipitatum Regel. against Multidrug Resistant Bacteria

The present study assessed the in vitro antibacterial and antibiofilm potential of hexane (ASHE) and dichloromethane (ASDE) extracts of Allium stipitatum (Persian shallot) against planktonic cells and biofilm structures of clinically significant antibiotic resistant pathogens, with a special emphasis on methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA), and emerging pathogens, Acinetobacter baumannii and Stenotrophomonas maltophilia. Antibacterial activities were determined through disk diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), time-kill kinetics, and electron microscopy. Antibiofilm activity was assessed by XTT [2,3-bis(2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide] reduction assay and by confocal laser scanning microscopy (CLSM). The zone of inhibition ranged from 13 to 33 mm, while the MICs and MBCs ranged from 16 to 1024 μg mL-1. Both ASHE and ASDE completely eradicated overnight cultures of the test microorganisms, including antibiotic resistant strains. Time-kill studies showed that the extracts were strongly bactericidal against planktonic cultures of S. aureus, MRSA, Acinetobacter baumannii, and S. maltophilia as early as 4 hours postinoculation (hpi). ASHE and ASDE were shown to inhibit preformed biofilms of the four biofilm phenotypes tested. Our results demonstrate the potential therapeutic application of ASHE and ASDE to inhibit the growth of gram-positive and gram-negative biofilms of clinical significance and warrant further investigation of the potential of A. stipitatum bulbs against biofilm-related drug resistance.

Molecular Characterization of Methicillin-Resistant Staphylococcus aureus Isolates, Isolated from a Burn Hospital in Southwest Iran in 2006 and 2014

OBJECTIVES

Incidence of methicillin-resistant Staphylococcus aureus (MRSA) is increasing every year, especially in burn patients with a high rate of morbidity and mortality. Molecular and epidemiologic studies are useful practices for understanding the relatedness of isolates in a single patient or a hospital. This study aimed at determining molecular characterizations of isolates collected in 2006 and 2014 using S. aureus-specific staphylococcal protein A (Spa) typing and Multilocus Sequence Typing (MLST) methods.

MATERIALS AND METHODS

Totally, 71 MRSA isolates were collected during the last two studies (2006 and 2014) from burn patients at Taleghani Burn Centre. After confirmation, all isolates were analysed using MLST and Spa typing methods.

RESULTS

We reported the emergence of Spa type t021, ST-30-IV MRSA isolates, which were PVL-positive in 14.6% of the cases and t12366, ST-8-IV isolates, which were PVL-negative in 9.8% of the cases. In 2014 study, Spa typing of MRSA isolates revealed five different spa types. Overall, in two studies, t037, ST-239, SCCmec III, and CC8 were predominant clones and they were reported in 63% of the cases.

CONCLUSION

The predominance of ST-239 in this region during the last eight years is a major concern. It also has a disturbing impact on the management of staphylococcal infections. Moreover, the SCCmec type IV strain is able to disseminate rapidly in hospital environments, demanding an improvement in infection-control policy.

Distribution of staphylococcal cassette chromosome mec types among methicillin-resistant coagulase negative staphylococci in central Iran

BACKGROUND AND OBJECTIVES

Methicillin-resistant coagulase-negative staphylococci (MR-CoNS) are important nosocomial pathogens. They may serve as a reservoir of SCCmec, the genomic island encoding amongst other methicillin resistance. This study was designed to determine the distribution of different SCCmec types from MR-CoNS isolated from clinical specimens in a tertiary hospital in central Iran, having high frequency of nosocomial methicillin-resistant staphylococcal infections.

MATERIALS AND METHODS

We evaluated isolates from patients attending the Vali-Asr Hospital located in the center of Iran, from February to December 2012. Multiplex PCR was performed for SCCmec typing. For isolates in which SCCmec could not be typed directly, additional ccr and mec complex analyses were performed.

RESULTS

Totally, 70 MR-CoNS isolates, comprising of 47 S. epidermidis strains (67%), 10 S. saprophyticus (14.3%), 9 S. hemolyticus (13%) and 4 S. lugdunensis (5.7%) were identified. Thirty-nine were characterized as type IVa 19 (27%), type III 11 (16%), type II 7 (10%) and type V 2 (3%). Only 20 isolates (28.6%) carried the ccr complex, while the current methods could not characterize the 11 remaining isolates.

CONCLUSION

A high level of SCCmec genetic diversity was found among MR-CoNS isolates. MR-CoNS may act as a reservoir of SCCmec IV for MRSA. This issue should be taken into consideration seriously.

Evaluation of Regulatory T Cells in Patients with Acute and Chronic Brucellosis

BACKGROUND

Brucellosis is one of the most common chronic diseases, with widespread distribution. In spite of cell-mediated immunity (CMI) modulated mainly via activated T-helper type 1 (Th1) cells, brucellosis can advance to chronic disease in about 10-30% of cases. Regulatory T cells (Treg cells) are involved the immune response to brucellosis; however, their role, particularly in the change from the acute to the chronic phase, have not yet been elucidated. The main hypothesis of this study was that Treg cells play critical roles in the progression of brucellosis from the acute to the chronic phase.

METHODS

Forty-eight unrelated subjects participated in this case-control study. The percentages of CD4+, CD25+, FoxP3+, and CD25/FoxP3+ T cells in the peripheral blood mononuclear cells (PBMCs) of acute (AB) and chronic brucellosis (CB) patients and healthy controls were determined by flow cytometry. The mean florescence intensities (MFIs) of CD4+, CD25+, and FoxP3+ T cells were also measured.

RESULTS

We found a significantly lower percentage of CD25/FoxP3+ Treg cells in CB than in the AB and control groups (p < 0.05). Also, CD4 and CD25 MFIs were significantly less in CB than in AB and controls (p < 0.05).

CONCLUSIONS

We propose that the reduced number of CD25/FoxP3+ Treg cells in the CB group leads to T cell anergy and this contributes to the development of chronic infection.

Comparing the Effect of Echinacea and Chlorhexidine Mouthwash on the Microbial Flora of Intubated Patients Admitted to the Intensive Care Unit

Background:

Providing intubated patients admitted to the intensive care units with oral healthcare is one of the main tasks of nurses in order to prevent Ventilator-Associated Pneumonia (VAP). This study aimed at comparing the effects of two mouthwash solutions (echinacea and chlorhexidine) on the oral microbial flora of patients hospitalized in the intensive care units.

Materials and Methods:

In this clinical trial, 70 patients aged between18 and 65 years undergoing tracheal intubation through the mouth in three hospitals in Arak, were selected using simple random sampling and were randomly divided into two groups: the intervention group and the control group. The oral health checklist was used to collect the data (before and after the intervention). The samples were obtained from the orally intubated patients and were then cultured in selective media. Afterwards, the aerobic microbial growth was investigated in all culture media. The data were analyzed using SPSS software.

Results:

The microbial flora in the echinacea group significantly decreased after the intervention (p < 0.0001) and it was also the case withmicrobial flora of the patients in the chlorhexidine group (p < 0.001). After 4 days, the oral microbial flora of the patients in the intervention group was lower than that of the patients in the control group (p < 0.001).

Conclusions:

The results showed that the echinacea solution was more effective in decreasing the oral microbial flora of patients in the intensive care unit. Given the benefits of the components of the herb Echinacea, it can be suggested as a viable alternative to chlorhexidine.

Frequency of Antiseptic Resistance Among Staphylococcus aureus and Coagulase-Negative Staphylococci Isolated From a University Hospital in Central Iran

OBJECTIVES

Reduced biocide susceptibility in Staphylococci is associated with various antiseptic resistance genes encoding efflux systems. Our aim was to determine the susceptibility to three disinfectant agents, including benzalkonium chloride (BAC), benzethonium chloride (BZT), and chlorhexidine digluconate (CHDG) among clinical isolates of Staphylococcus aureus and coagulase-negative Staphylococci (CoNS).

METHODS

The minimum inhibitory concentration (MIC) of 60 methicillin-resistant S. aureus (MRSA), 54 methicillin-sensitive S. aureus (MSSA) and 51 CoNS isolates from a single hospital to three biocidal agents (BAC, BZT, and CHDG) was determined. Biocide resistance genes (qacA/B, smr, qacG, qacH, qacJ, and norA) were analyzed by the polymerase chain reaction assay.

RESULTS

All isolates had MICs for BAC and BZT from 0.25 to 8 µg/mL, and for CHDG from 0.5 to 64 µg/mL. qacA/B was the most common biocide resistance gene among all 165 Staphylococcus isolates (76; 46%), which comprised 38 (63.3%) MRSA, 14 (25.9%) MSSA, and 24 (47%) CoNS. Eleven (6.7%) and 24 (14.5%) isolates among the 165 Staphylococci carried smr and norA genes, respectively. In contrast, other resistance genes such as qacG, qacH, and qacJ were absent in all Staphylococci studied. The qacA/B and smr genes were detected concomitantly in 3% of isolates, and 23.6% strains of the total 165 Staphylococcus isolates were negative for each studied gene.

CONCLUSIONS

The carriage of several biocide resistance genes, including qacA/B, smr, and norA, alone or concurrently, is associated with reduced susceptibility. Use of antiseptics may select for antibiotic-resistant strains and assist their survival in the healthcare environment.

Specific detection of common pathogens of acute bacterial meningitis using an internally controlled tetraplex-PCR assay

Accurate and timely diagnosis of acute bacterial meningitis is critical for antimicrobial treatment of patients. Although PCR-based methods have been widely used for the diagnosis of acute meningitis caused by bacterial pathogens, the main disadvantage of these methods is their high cost. This disadvantage has hampered the widespread use of molecular assays in many developing countries. The application of multiplex assays and "in-house" protocols are two main approaches that can reduce the overall cost of a molecular test. In the present study, an internally controlled tetraplex-PCR was developed and validated for the specific detection of Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae in cerebrospinal fluid (CSF) samples. The analysis of a panel of other human pathogens showed no cross-reactivity in the assay. The analytical sensitivity of the in-house assay was 792.3 copies/ml, when all three bacteria were presentin the specimens. This value was calculated as 444.5, 283.7, 127.8 copies/ml when only S. pneumoniae, N. meningitidis and H. influenzae, respectively, were present. To demonstrate the diagnostic performance of the assay, a total of 150 archival CSF samples were tested and compared with a commercial multiplex real-time PCR kit. A diagnostic sensitivity of 92.8% and a specificity of 95.1% were determined for the present tetraplex-PCR assay. The results indicate that the established method is sensitive, specific and cost-effective, and can be used particularly in situations where the high cost of commercial kits prevents the use of molecular methods for the diagnosis of bacterial meningitis.

In Vitro and in Vivo Antistaphylococcal Activity Determination of the New Recombinant Lysostaphin Protein

Background:

Bacterial infection by antibiotic-resistant Staphylococcus aureus strains is a worldwide concern and the development of novel antistaphylococcal agents is acutely needed. Lysostaphin, an example of such novel agents, is a bacteriocin secreted by S. simulans to kill S. aureus through proteolysis of the Staphylococcus cell wall.

Objectives:

The aim of this study was to evaluate the in vitro and in vivo antistaphylococcal activity of recombinant lysostaphin.

Materials and Methods:

The in vitro study of the recombinant lysostaphin activity against S. aureus was determined by turbidimetric assay. For in vivo investigation, two groups of rats were inoculated with 1.4 × 10⁹ CFU S. aureus. Five days after the nasal instillation of S. aureus, treatment in one of the groups was performed with a single dose (200 μg/dose) of recombinant lysostaphin formulated in Eucerin-based cream.

Results:

Recombinant lysostaphin at 100 μg/mL concentration showed a significant decrease of the optical density compared to the control samples. The in vivo study demonstrated that a single dose (200 μg/dose) of recombinant lysostaphin cream significantly reduced nasal colonization in all the treated animals compared to the untreated ones.

Conclusions:

These results demonstrated that the recombinant lysostaphin produced in this study was able to kill nasal S. aureus in rats. It can be recommended for human clinical trial studies.

The Dynamic of Staphylococcus aureus Nasal Carriage in Central Iran

BACKGROUND

Nasal carriage of Staphylococcus aureus plays an important role in the pathogenesis of staphylococcal infections. Anterior nasal region is a primary origin of S. aureus. In longitudinal studies, three types of S. aureus nasal carriers can be distinguished: persistent carriers, intermittent or transient carriers, and noncarriers.

OBJECTIVES

This study was designed to determine the dynamic of S. aureus nasal carriage in healthy carriers of central Iran.

PATIENTS AND METHODS

A total of 813 healthy adults were subjected to this cross-sectional study from November 2011 to January 2012 in Arak University of Medical Sciences. Two anterior nasal swabs were taken with a week interval from each participant. All the isolates were identified as S. aureus phenotypically by standard laboratory methods. The isolates were reconfirmed by amplification of sa442 gene as the identification marker. All the isolates were screened for the presence of the PVL (Panton-Valentine leukocidin) virulence genes and arginine catabolic mobile element (ACME-arc).

RESULTS

Among the 813 subjects screened, 83 (10.2%) were persistent carriers, 86 (10.6%) were transient carriers and 644 (79.2%) cases were found as noncarriers. A total of 169 (20.8%) participants had colonized S. aureus. The frequency of ACME-arc A and PVL genes in S. aureus strains were 17% and 20%, respectively.

CONCLUSIONS

Carriage of PVL-positive S. aureus is common in this region, even in the low frequency of MRSA colonization. The detection of ACME-arcA gene in S. aureus isolates is a public-health concern and demands continued surveillance and close monitoring.

Application of Reverse Transcriptase -PCR (RT-PCR) for rapid detection of viable Escherichia coli in drinking water samples

BACKGROUND

Polymerase chain reaction (PCR) is preferred to other methods for detecting Escherichia coli (E. coli) in water in terms of speed, accuracy and efficiency. False positive result is considered as the major disadvantages of PCR. For this reason, reverse transcriptase-polymerase chain reaction (RT-PCR) can be used to solve this problem. The aim of present study was to determine the efficiency of RT-PCR for rapid detection of viable Escherichia coli in drinking water samples and enhance its sensitivity through application of different filter membranes.

MATERIALS AND METHODS

Specific primers were designed for 16S rRNA and elongation Factor II genes. Different concentrations of bacteria were passed through FHLP and HAWP filters. Then, RT-PCR was performed using 16srRNA and EF -Tu primers. Contamination of 10 wells was determined by RT-PCR in Arak city. To evaluate RT-PCR efficiency, the results were compared with most probable number (MPN) method.

RESULTS

RT-PCR is able to detect bacteria in different concentrations. Application of EF II primers reduced false positive results compared to 16S rRNA primers. The FHLP hydrophobic filters have higher ability to absorb bacteria compared with HAWB hydrophilic filters. So the use of hydrophobic filters will increase the sensitivity of RT-PCR.

CONCLUSION

RT-PCR shows a higher sensitivity compared to conventional water contamination detection method. Unlike PCR, RT-PCR does not lead to false positive results. The use of EF-Tu primers can reduce the incidence of false positive results. Furthermore, hydrophobic filters have a higher ability to absorb bacteria compared to hydrophilic filters.

Characterization of Plasmid-Mediated AmpC and Carbapenemases among Iranain Nosocomial Isolates of Klebsiella pneumoniae Using Phenotyping and Genotyping Methods

OBJECTIVES

Plasmid-mediated AmpC β-lactamases (PMABLs) and carbapenemases are emerging groups of antimicrobial-resistance determinants. The aims of the study were to evaluate the occurrence of PMABLs and carbapenemases in clinical isolates of Klebsiella pneumoniae and compare the test performance of various phenotypic methods for detection of these enzymes in Iran.

METHODS

A total of 100 K. pneumoniae isolates were collected from clinical specimens obtained in Valiasr Hospital. AmpC production in all isolates was determined using the AmpC disk test, the cephamycin Hodge test, the AmpC Etest, and the boronic acid combined-disk test. In addition, carbapenemase production was determined using the modified Hodge test, the EDTA disk synergy test, and the boronic acid combined-disk test. The performances of various phenotypic methods were evaluated by the comparison of their results with polymerase chain reaction (PCR) method as the gold standard.

RESULTS

Of the 100 isolates, 19 (19%) were demonstrated to harbor the PMABL-resistance gene by the multiplex PCR method. The PCR result indicated the presence of carbapenemase genes in 12 isolates. The performance of various phenotypic tests carried out for detection of carbapenemase-producing isolates varied widely, ranging in sensitivity from 30% to 100% and in specificity from 90.8% to 100%.

CONCLUSION

This is the first report of MOX-type AmpC β-lactamase and bla GES in K. pneumoniae in Iran. A comparison of the phenotypic methods showed that a combination of cefoxitin plus boronic acid is optimal for detecting plasmid-mediated AmpC enzymes in K. pneumoniae, whereas the implementation of molecular methods is often complex, requires specially trained personnel, and is associated with higher costs.

Detection of algD, oprL and exoA Genes by New Specific Primers as an Efficient, Rapid and Accurate Procedure for Direct Diagnosis of Pseudomonas aeruginosa Strains in Clinical Samples

Background:

Pseudomonas aeruginosa is an opportunistic pathogen that infects patients with cystic fibrosis, burning wounds, ophthalmic traumas and immunodeficiency.

Objectives:

The aim of the present study was to compare the efficiency of newly designed primer sets with some previously published primers for PCR detection of exoA, oprL and algD genes from P. aeruginosa.

Materials and Methods:

A total of 150 clinical specimens were inoculated into the routine and selective culture media for P. aeruginosa isolation. Specific primers were designed by bioinformatics analysis for detection of the virulence genes determinants, exoA, oprL and algD. The sequences of these three genes were obtained from NCBI and multiple alignments were performed to find the conserved sequences of each gene to design the primers. Multiple alignment and primer design steps were carried out by the AlleleID software, version 7.0.

Results:

Microbiological culture methods resulted 70 P. aeruginosa strains isolated from 70 of the 150 clinical specimens. The results of the PCR assay using the newly designed exoA, oprL and algD primer sets were positive in 68, 70 and 69 clinical samples which represent 97.2%, 100% and 98% sensitivity for each primer set, respectively. The PCR results using previously published exoA, oprL and algD primer sets were positive only in 57, 49 and 28 specimens that correspond to 81.5%, 70% and 40% sensitivity, respectively.

Conclusions:

The results of the present study showed that in comparison with previously published primer sets, P. aeruginosa infection can be diagnosed with higher sensitivity and specificity by the conventional PCR assay using the newly designed primers. It was also shown that the results of the PCR assay on clinical samples of severe infections became positive much earlier than the results of conventional culture method.

Naloxane enhanced inhibitory effect of verapamil on seizure induced by pentylenetetrazol in male rats

The role of opioid receptor and voltage dependent calcium channels on the kindling induced by the convulsant pentylenetetrazole (PTZ) were investigated in the rats. Experiment involved 24 rats which were divided into four groups. Kindling was established with PTZ in subconvulsive dose (37.5 mg/kg i.p.) every 48 h and effects were observed within 20 min using five-point scoring system. All animals were kindled to three consecutive-stage five seizures and their stability was tested. Saline, verapamil (calcium channel blocker), naloxone (opioid antagonist) or both of them were then administrated 20 min before PTZ application. Convulsant parameters were significantly (P<0.05) reduced by verapamil. Naloxone had no significant effect on the seizure expression of fully kindled animals, whereas simultaneous application of naloxone and verapamil had profound inhibitory effect on all seizure parameters. The results of the present study suggest that naloxane increased the inhibitory effect of verapamil on the seizure induced by PTZ kindling.

Genotypically different clones of Staphylococcus aureus are diverse in the antimicrobial susceptibility patterns and biofilm formations

This study evaluated whether genotypically different clinical isolates of S. aureus have similar susceptibilities to individual antibiotics. It further aims to check the impact of biofilm on the in vitro activity of vancomycin, daptomycin, linezolid, and tigecycline against S. aureus clones. The study used a total of 60 different clinical MSSA and MRSA isolates. Susceptibilities were performed in planktonic cultures by macrobroth dilution and epsilon-test (E test) system. Biofilm production was determined using an adherent plate assay. The efficacy of antimicrobial activities against biofilms formation was checked using confocal laser scanning microscopy (CLSM). The study found that similar and different spa, MLST, and SCCmec types displayed high variation in their susceptibilities to antibiotics with tigecycline and daptomycin being the most effective. The biofilms were found resistant to high concentrations of most antibiotics tested with daptomycin being the most effective drug used in adhesive biofilms. A considerable difference exists among similar and various clone types against antibiotics tested. This variation could have contributed to the degree of virulence even within the same clonal genotype and enhanced heterogeneity in the infection potential. Thus, the development of a rapid and precise identification profile for each clone in human infections is important.

Novel cassette array in a class 1 integron in clinical isolates of Acinetobacter baumannii from central Iran

Antibiotic resistance in Acinetobacter baumannii is a major problem in the hospital and outbreaks caused by this organism have been reported frequently. The present study aimed at determining the antibiotic susceptibility patterns, the prevalence of different classes of integrons and the characterization of integron class 1 gene cassettes in Iranian A. baumannii isolates. A total of 63 non-duplicate A. baumannii isolates were collected from clinical and environmental specimens in the Vali-Asr hospital in the central province of Iran (March to September, 2011). The antimicrobial susceptibility for 15 antibiotics which are used conventionally was determined by disk diffusion. The presence of different integron classes was investigated by PCR and the size of gene cassettes in class 1 integrons was then determined by PCR as well. Moreover, integron cassette arrays of isolates were delineated by RFLP and sequencing amplicons with different lengths. Of 63 isolates 62 (98.4%) carried a class 1 integron. The prevalence of IntI2 was 15.9% and the length of the amplicons ranged from 500 bp to 3 kb. Sequencing of integrons of class 1 revealed the presence of many resistance genes (aadA, aacA, aacC, dfrA, bla(GES) and bla(IMP)). We identified a completely new gene cassette which contained aacA7-qacF-aadA5-bla(IMP), this cassette has not been reported previously in A. baumannii.

Short repeats in the spa gene of Staphylococcus aureus are prone to nonsense mutations: stop codons can be found in strains isolated from patients with generalized infection

Fifteen sequences with stop codons have been obtained in the course of standard methicillin-resistant Staphylococcus aureus (MRSA) spa typing. In nine of those sequences, stop codons occurred due to nonsense G-T and A-T transversions. G-T transversions would appear to be frequent in the spa gene, mostly due to symmetric mutational AT-pressure in the whole S. aureus genome and due to replication-associated mutational pressure characteristic of lagging strands of the "chromosome". A-T transversions would appear to be frequent in the spa gene mostly due to transcription-associated mutational pressure. Relative to other S. aureus genes, short repeats in spa are enriched by nonsense sites for G-T and A-T transversions; the probability of being nonsense for A-T transversion is high in that part of spa coding region. 13 out of 15 (87%) of the sequences with stop codons were obtained from strains isolated from patients with generalized S. aureus infection. Truncation of spa at its C-terminus is predicted to result in a protein that possesses functional IgG binding domains unable to be linked to the cell wall. This is discussed in light of the known fact that extracellular spa is a strong virulence factor involved in immune evasion.

Expression and Antigenic Evaluation of VacA Antigenic Fragment of Helicobacter Pylori

Objective(s) : Helicobacter pylori, a human specific gastric pathogen is a causative agent of chronic active gastritis. The vacuolating cytotoxin (VacA) is an effective virulence factor involved in gastric injury. The aim of this study was to construct a recombinant protein containing antigenic region of VacA gene and determine its antigenicity.

MATERIALS AND METHODS

The antigenic region of VacA gene was detected by bioinformatics methods. The polymerase chain reaction method was used to amplify a highly antigenic region of VacA gene from chromosomal DNA of H. pylori. The eluted product was cloned into the prokaryotic expression vector pET32a. The target protein was expressed in the Escherichia coli BL21 (DE3) pLysS. The bacteria including pET32a-VacA plasmids were induced by IPTG. The antigenicity was finally studied by western blotting using sera of 15 H. pylori infected patients after purification.

RESULTS

Enzyme digestion analysis, PCR and DNA sequencing results showed that the target gene was inserted correctly into the recombinant vector. The expressed protein was purified successfully via affinity chromatography. Data indicated that antigenic region of VacA protein from Helicobacter pylori was recognized by all 15 patient's sera. Conclusion : Our data showed that antigenic region of VacA protein can be expressed by in E . co.li. This protein was recognized by sera patients suffering from H. pylori infection. the recombinant protein has similar epitopes and close antigenic properties to the natural form of this antigen. Recombinant antigenic region of VacA protein also seems to be a promising antigen for protective and serologic diagnosis .

Molecular characterization of the first community-acquired methicillin-resistant Staphylococcus aureus strains from Central Iran

BACKGROUND

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has spread throughout the world with varying regional incidences and different staphylococcal cassette chromosome mec (SCCmec) elements in different genetic backgrounds. No information is available on CA-MRSA in Iran. A cross-sectional study was carried out among healthy students to investigate: (1) the prevalence of CA-MRSA in Central Iran, (2) the molecular epidemiology of such CA-MRSA strains, (3) the antimicrobial resistance patterns of the strains, and (4) the distribution of virulence genes in these CA-MRSA strains.

METHODS

A total of 700 nasal swabs were collected and subjected to S. aureus and MRSA-specific isolation procedures. Antimicrobial resistance patterns were determined using the disk diffusion method, and molecular typing was carried out by multi-locus sequence typing (MLST), SCCmec typing, and Staphylococcus protein A (spa) typing for all CA-MRSA isolates. PCR was used to detect various virulence genes.

RESULTS

One hundred fifty-four S. aureus strains were isolated from the anterior nares of 700 healthy students. According to the US Centers for Disease Control and Prevention definitions for CA-MRSA, seven (4.5%) isolates were confirmed as CA-MRSA. CA-MRSA isolates belonged to SCCmec types IV (n = 6) and V (n = 1). The predominant spa-type among the CA-MRSA isolates was t790 (n = 3), with single t660, t084, and t325 isolates; one isolate was not typeable. The predominant sequence type was ST22, t790, SCCmec IV in three isolates, and the four other sequence types were ST25, ST859, ST14, and ST15.

CONCLUSIONS

Iranian CA-MRSA strains are genetically diverse with an elevated prevalence of t790/ST22 SCCmec IV isolates. These findings support the need for more effective infection control measures to reduce nasal carriage and prevent dissemination of CA-MRSA in Iran.

Diversity in the antimicrobial susceptibility patterns of methicillin-resistant Staphylococcus aureus clones

Methicillin-resistant Staphylococcus aureus (MRSA) is well known for its epidemicity, with the emergence of new clones on a daily basis. Diversity in the clonal types of MRSA challenges the success of treatment, as different clones respond to different sets of antibiotics. However, the antibiotic susceptibility among the isolates within the same clones is largely unexplored. In a previous study on MRSA epidemiology in Malaysia, we identified six major clonal complexes (ST-239-CC8, ST-1-CC1, ST-188-CC1, ST-22-CC22, ST-7-CC7 and ST-1283-CC8). In the present study, we investigated the antibiotic susceptibility patterns of isolates of different clones. Three hundred and eighty-nine MRSA isolates were subjected to the disc diffusion test, oxacillin minimum inhibitory concentration (MIC) determination and assessment of the distribution of macrolide, lincosamide and streptogramin B (MLS(B)) resistance genes. Thirty-six different antibiotic profiles were observed: 30 (83.3 %) among ST-239, 2 (5.6 %) among ST-1283 and 1 (2.8 %) each for ST-1, ST-7, ST-22 and ST-188. All ST-239 (362, 9 %) isolates were multiple drug-resistant (MDR; resistant to more than three classes of antibiotics) and had oxacillin MICs >256 mg/l. Among the 385 clindamycin-resistant isolates, 375 (96.4 %) illustrated inducible resistance (D-zone-positive), while 10 (2.6 %) showed constitutive resistance. The vast majority of the macrolide-resistant isolates carried the ermA gene (95.1 %), followed by ermC (12.9 %). Diversity in the antibiotic susceptibilities of isolates within the clones emphasises the need for continuous surveillance of MDR strains to prescribe the correct antibiotic rather than empirical treatment. This will likely reduce the emergence of new endemic or epidemic resistant MRSA clones.

Evaluation of viral antibodies in Iranian multiple sclerosis patients

OBJECTIVE

To evaluate the viral antibodies in new Iranian multiple sclerosis (MS) patients.

METHODS

In a cross-sectional study, sera from 61 MS patients and 60 healthy individuals were collected from January 2009 to March 2010 in the Immunology Department of Arak University of Medical Sciences, Arak, Iran, and examined for the presence of the anti-Epstein-Barr virus (EBV), human herpes virus 6 (HHV-6), measles, mumps, and para-influenza viruses IgG and IgM using an enzyme-linked immunosorbent assay or immunofluorescence.

RESULTS

There were significant differences between the MS patients and the healthy individuals (controls) in the seroprevalence of anti-HHV-6 IgM (odds ratio [OR]=4.3, 95% confidence interval [CI]=2-9.3, p=0.001); anti-HHV-6 IgG (OR=2, 95% CI=1-4, p=0.04); anti-measles IgM (OR=3.2, 95% CI=1.5-6.9, p=0.002); and the anti-mumps IgM (OR=4.1, 95% CI=1.9-8.8, p=0.0001) and IgG (OR=9.5, 95% CI=3-29.6, p=0.0001). Almost all MS patients and the control individuals were negative to EBV and parainfluenza IgM.

CONCLUSION

These results confirm an association between the incidence of MS and the antibodies to HHV-6 and the measles and mumps viruses, and show induction of a primary immune response (IgM), or virus reactivation, in MS patients. These viruses may have an important role in development of MS as an initial trigger in this geographical area.

mec-associated dru typing in the epidemiological analysis of ST239 MRSA in Malaysia

The usefulness of mec-associated dru typing in the epidemiological analysis of methicillin-resistant Staphylococcus aureus (MRSA) isolated in Malaysia was investigated and compared with pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and spa and SCCmec typing. The isolates studied included all MRSA types in Malaysia. Multilocus sequence type ST188 and ST1 isolates were highly clonal by all typing methods. However, the dru typing of ST239 isolates produced the clearest discrimination between SCCmec IIIa and III isolates, yielding more subtypes than any other method. Evaluation of the discriminatory power for each method identified dru typing and PFGE as the most discriminatory, with Simpson's index of diversity (SID) values over 89%, including an isolate which was non-typeable by spa, but dru-typed as dt13j. The discriminatory ability of dru typing, especially with closely related MRSA ST239 strains (e.g., Brazilian and Hungarian), underscores its utility as a tool for the epidemiological investigation of MRSA.

Prevalence of mutations at codon 463 of katG gene in MDR and XDR clinical isolates of Mycobacterium tuberculosis in Belarus and application of the method in rapid diagnosis

Isoniazid (INH) is a central component of drug regimens used worldwide to treat tuberculosis. In respect to high GC content of Mycobacterium tuberculosis, nonsynonymous mutations are dominant in this group. In this study a collection of 145 M. tuberculosis isolates was used to evaluate the conferring mutations in nucleotide 1388 of katG gene (KatG463) in resistance to isoniazid. A PCR-RFLP method was applied in comparison with DNA sequencing and anti-mycobacterial susceptibility testing. From all studied patients, 98 (67.6%) were men, 47 (32.4%) were women, 3% were <15 and 9% were >65 years old; male to female ratio was 1:2.4. PCR result of katG for a 620-bp amplicon was successful for all purified M. tuberculosis isolates and there was no positive M. tuberculosis culture with PCR negative results (100% specificity). Subsequent PCR RFLP of the katG identified mutation at KatG463 in 33.3%, 57.8% and 59.2% of our clinically susceptible, multidrug resistant TB (MDR) and extensively drug resistant (XDR) isolates, respectively. Strains of H37Rv and Academic had no any mutations in this codon. M. bovis was used as a positive control for mutation in KatG463. Automated DNA sequencing of the katG amplicon from randomly selected INH-susceptible and resistant isolates verified 100% sequence accuracy of the point mutations detected by PCR-RFLP. We concluded that codon 463 was a polymorphic site that is associated to INH resistance (a missense or "quiet" mutation). RFLP results of katG amplicons were identical to those of sequence method. Our PCR-RFLP method has a potential application for rapid diagnosis of M. tuberculosis with a high specificity.