The efficacy of lyticase and ß-glucosidase enzymes on biofilm degradation of Pseudomonas aeruginosa strains with different gene profiles.

BACKGROUND: Pseudomonas aeruginosa is a nosocomial pathogen that causes severe infections in immunocompromised patients. Biofilm plays a significant role in the resistance of this bacterium and complicates the treatment of its infections. In this study, the effect of lyticase and ß-glucosidase enzymes on the degradation of biofilms of P. aeruginosa strains isolated from cystic fibrosis and burn wound infections were assessed. Moreover, the decrease of ceftazidime minimum biofilm eliminating concentrations (MBEC) after enzymatic treatment was evaluated. RESULTS: This study demonstrated the effectiveness of both enzymes in degrading the biofilms of P. aeruginosa. In contrast to the lyticase enzyme, ß-glucosidase reduced the ceftazidime MBECs significantly (P < 0.05). Both enzymes had no cytotoxic effect on the A-549 human lung carcinoma epithelial cell lines and A-431 human epidermoid carcinoma cell lines. CONCLUSION: Considering the characteristics of the ß-glucosidase enzyme, which includes the notable degradation of P. aeruginosa biofilms and a significant decrease in the ceftazidime MBECs and non-toxicity for eukaryotic cells, this enzyme can be a promising therapeutic candidate for degradation of biofilms in burn wound patients, but further studies are needed.

Epidemiology of echinococcosis in Iran: a systematic review and meta-analysis.

BACKGROUND: Echinococcosis is a zoonotic disease caused by the larval stages of taeniid cestodes of the genus Echinococcus. The two major types of infection in humans are cystic echinococcosis (CE) or hydatidosis and alveolar echinococcosis (AE). It is endemic in some parts of the world, such as the Middle East, with Iran being a part of it. This systematic review and meta-analysis were conducted to determine the prevalence of CE and AE echinococcosis and their epidemiological and clinical aspects in Iran. METHODS: Electronic databases, including MEDLINE (via PubMed), SCOPUS, Web of Science, SID and Mag Iran (two Persian scientific search engines) were searched from 1 January 1990 to 8 August 2017. The prevalence of CE and AE echinococcosis was estimated using the random effects meta-analysis. Heterogeneity was evaluated by subgroup analysis. Data were analyzed by STATA version 12. RESULTS: Of the 2051 records identified in the mentioned electronic databases, Seventy-eight articles met our eligibility criteria, with a total of 214124individuals. The meta-analysis was performed on only 37 out of 78 included studies. The pooled prevalence of CE and AE in Iran was 5% [95% confidence interval )CI(: 3-6%] and 2% [95% CI: 0-5%], respectively. Subgroup meta-analysis revealed that the prevalence of CE was significantly higher in North [9%, 95% CI: 4-18%] and West of Iran [6%, 95% CI: 3-11%], patients younger than 40 years of age [7%, 95% CI: 4-12%], villagers and nomads [6%, 95% CI: 2-12%], and studies that used the combination of serological, clinical, and imaging diagnostic methods [7%, 95% CI: 5-9%]. There were no significant differences between the prevalence of CE among low and high-quality studies. Housewives were the most affected group by hydatidosis (n=24/77, 31%), followed by illiterate people (n=11/77, 14%) and farmers (n= 9/77, 12%). Liver [55%, 95% CI: 46-65%] and lung [28%, 95% CI, 22-35%] were the most common sites of cyst formation. CONCLUSIONS: Given to the importance of echinococcosis on human health and domestic animals industry, it is necessary to implement monitoring and control measures in this regard.

Diagnostic accuracy of interferon (IFN)-γ inducible protein 10 (IP-10) as a biomarker for the discrimination of active and latent tuberculosis.

To assess the potency of Interferon (IFN)-γ inducible protein 10 (IP-10) stimulated by recombinant PE35 and PPE68 as a biomarker in differentiating between active and latent tuberculosis. Patients with active pulmonary TB (PTB) (n = 30), latent TB infection (LTBI) (n = 29), and BCG-vaccinated healthy controls (HCs) (n = 30) were enrolled and blood samples were taken from them. The diagnostic performance of IP-10 was evaluated by the Receiver operator characteristic (ROC) curve and the area under the curve (AUC) and their 95% confidence intervals (CI) were calculated. The median IP-10 concentrations following stimulation with recombinant PE35 and PPE68 were significantly higher in TB-infected group (both PTB and LTBI) compared with HCs (P < 0.05). It was also significantly higher in PTB patients compared with individuals with LTBI (P < 0.05). The discriminatory performance of IP-10 following stimulation with recombinant PE35 and PPE68 (assessed by AUC) between TB patients and HCs were similar (AUC: 0.79 [95% CI 0.68-0.89] and 0.79 [95% CI 0.69-0.89], respectively). AUCs of IP-10 following stimulation with recombinant PE35 and PPE68 for distinguishing between PTB and LTBI groups were 0.63 (95% CI 0.47-0.79) and 0.61 (0.45-0.77), respectively. Under the selected cut-off values, the sensitivity and specificity of IP-10 for distinguishing of TB-infected and HCs after stimulation with recombinant PE35 was 74.5% and 73%, respectively and after stimulation with recombinant PPE68 were 76.5% and 63%, respectively. Moreover, the sensitivity and specificity of IP-10 for differentiating of PTB and LTBI following stimulation with recombinant PE35 and PPE68 were 770 pg/ml (sensitivity: 63%; specificity: 62%) and 502 pg/ml (sensitivity: 80%; specificity: 52%), respectively. IP-10 stimulated by recombinant PE35 and PPE68 is a promising biomarker for TB diagnosis. However, it doesn't have desirable sensitivity and specificity in distinguishing between PTB and LTBI.

Epidemiologic, clinical, and laboratory characteristics of childhood brucellosis : A study in an Iranian children's referral hospital.

BACKGROUND: Brucellosis is endemic in Iran. Children constitute 20-25% of cases. We determined clinical, laboratory, and epidemiologic characteristics of pediatric brucellosis patients hospitalized at the Children's Medical Center from May 2011 to December 2016. METHODS: Medical records were reviewed retrospectively. For each patient, a questionnaire was provided containing demographic characteristics (sex, age, nationality, date of admission, city of residence, history of ingestion of unpasteurized dairy products, family history of brucellosis, history of contact with suspicious animals) and clinical information (signs and symptoms, laboratory findings, history of disease relapse, treatment). RESULTS: Included were 43 patients diagnosed with brucellosis (26 males, 60.5%; age 1-13 years, mean ± SD: 7.02 ± 3.5). A history of ingestion of raw or unpasteurized dairy products was present in 88% (N = 38) and 11 patients (26%) had had contact with a suspicious animal. Highest frequencies of brucellosis were recorded in 2013 (N = 10, 23%) and 2015 (N = 11, 26%). Most cases were admitted in the summer (N = 14, 33%) and spring (N = 12, 28%). Fever (N = 39, 91%), arthralgia (N = 33, 77%), and malaise (N = 33, 77%) were the main complaints. Anemia (65%), lymphocytosis (51%), and elevated erythrocyte sedimentation rate (86%) and C­reactive protein (67%) were the most prominent blood anomalies. Blood culture was positive in 30% (N = 11/37), bone marrow culture in 31% (N = 4/11). A positive Wright, Coombs Wright, and 2 ME test was observed in 67% (N = 29), 92% (N = 34/37), and 85% (N = 34/40) of cases, respectively. Median length of antibiotic therapy was 12 weeks (2-24 weeks). The most frequent drug regimen was combined trimethoprim-sulfamethoxazole and rifampicin (N = 24, 56%). Relapse occurred in 9 patients (21%), there were no deaths. CONCLUSIONS: Physicians should be aware of the manifestations, diagnosis, and treatment protocols of childhood brucellosis. Control programs and preventive measures, e.g., regular examination of domestic animals, mass vaccination of livestock, slaughter of infected animals, control of animal trade and migration, pasteurization of milk and milk products, training and increased public awareness of the dangers of consumption of unpasteurized dairy products, are highly recommended.

Identification of Etiologic Agents of the Pertussis-like Syndrome in Children by Real-time PCR Method.

The aim of this study was to recognize the identity and frequency of etiologic agents of the pertussis-like syndrome in children < 2 years of age. A cross-sectional hospital-based study conducted from August 2014 to August 2015. All children < 2 years of age (n=100) who were suspected as pertussis infected were enrolled in this study and tested for Bordetella pertussis, adenovirus (Adv), respiratory syncytial virus (RSV), human metapneumovirus (hMPV), and influenza virus A (INF-A) by real-time PCR technique. RSV was the most detected pathogen (20%), followed by B. pertussis (18%), Adv (16%), INF-A (11%), and hMPV (10%). Co-infection was observed in 8 patients (11%) and the combinations of RSV/INF-A (n=3, 4%), and AdV/B. pertussis (n=3, 4%) were more frequent. RSV, B. pertussis, and hMPV were more frequent pathogens among infants < 4 months of age. However, Adv and INF-A were more frequent pathogens among children > 6 months of age. In this study, RSV was the most frequent identified pathogen (n=20, 20%), followed by B. pertussis (n=18, 18%) and AdV (n=16, 16%). Pertussis was more frequent in spring (8%) and summer (6%). In addition, clinical symptoms of pertussis were the same as some viral pathogens, which can lead to misdiagnosis of infection. Therefore, diagnosis of pertussis should be established on the bases of both the clinical symptoms and the laboratory methods.

Oral bacteriophages: metagenomic clues to interpret microbiomes.

Bacteriophages are bacterial viruses that are distributed throughout the environment. Lytic phages and prophages in saliva, oral mucosa, and dental plaque interact with the oral microbiota and can change biofilm formation. The interactions between phages and bacteria can be considered a portion of oral metagenomics. The metagenomic profile of the oral microbiome indicates various bacteria. Indeed, there are various phages against these bacteria in the oral cavity. However, some other phages, like phages against Absconditabacteria, Chlamydiae, or Chloroflexi, have not been identified in the oral cavity. This review gives an overview of oral bacteriophage and used for metagenomics. Metagenomics of these phages deals with multi-drug-resistant bacterial plaques (biofilms) in oral cavities and oral infection. Hence, dentists and pharmacologists should know this metagenomic profile to cope with predental and dental infectious diseases.

Staphylococcus aureus Dormancy: Waiting for Insurgency.

Relapse infection usually results from resistance to the antibiotic, acquired genes, or persister cells. Persister cells are formed through mutation, reduced activity or metabolically inactive pathways induced by antibiotics, harassing conditions, low ATP, and malnutrition. These factors provide the ground for bacteria to grow slowly. Such a slow growth rate makes traditional antibiotics ineffective against persister cells. Staphylococcus aureus (S. aureus), in addition to this form, can be observed in Small Colony Variants (SCVs), L-forms, and dormant, all of which are characterized by at least one feature, i.e., slow growth. Despite their slow growth, they are metabolically active in terms of stringent SOS and cell wall stress responses. The stress response involves resistance against harassing conditions, and it survives until it is reactivated later. The present study aims to discuss the mechanisms of all persister cell formations, circumstances involved, gene mutation, and adoptable strategies against it.

Factors associated with treatment failure, and possible applications of probiotic bacteria in the arsenal against Helicobacter pylori.

INTRODUCTION: Helicobacter pylori is a widespread helical Gram-negative bacterium, which causes a variety of stomach disorders, such as peptic ulcer, chronic atrophic gastritis, and gastric cancer. This microbe frequently colonizes the mucosal layer of the human stomach and survives in the inhospitable microenvironment, by adapting to this hostile milieu. AREAS COVERED: In this extensive review, we describe conventional antibiotic treatment regimens used against H. pylori including, empirical, tailored, and salvage therapies. Then, we present state-of-the-art information about reasons for treatment failure against H. pylori. Afterward, the latest advances in the use of probiotic bacteria against H. pylori infection are discussed. Finally, we propose a polymeric bio-platform to provide efficient delivery of probiotics for H. pylori infection. EXPERT OPINION: For effective probiotic delivery systems, it is necessary to avoid the early release of probiotics at the acidic stomach pH, to protect them against enzymes and antimicrobials, and precisely target H. pylori bacteria which have colonized the antrum area of the stomach (basic pH).

Clinical efficacy of probiotics in prevention of infectious diseases among hospitalized patients in ICU and non-ICU wards in clinical randomized trials: A systematic review.

Background and Aims: The present study aimed to review probiotics' clinical efficacy in preventing infectious diseases among hospitalized patients in ICU and non-ICU wards. Methods: A search of Medline, EMBASE, The Cochrane Library, Science Direct, Open Grey, and Google Scholar was conducted for eligible publications from 2002 to 2020 following the requirements outlined in the PRISMA guideline. The search strategy was based on the combination of the following terms: "probiotics," "prebiotics," "synbiotics," and "cross-infection." The logical operators "AND" (or the equivalent operator for the databases) and "OR" (e.g., probiotics OR prebiotics OR synbiotics) were used. Results: The results indicated that the probiotic consumption caused a significant reduction in antibiotic-associated diarrhea (AAD) and Clostridioides difficile infection (CDI) in 2/8 randomized clinical trials (RCTs) investigating AAD/CDI. Also, 5/12 clinical trials highlighted the considerable effects of probiotics on the reduction or prevention of ventilator associated pneumoniae (VAP), so the mean prevalence of VAP was lower in the probiotic group than in the placebo group. The total rate of nosocomial infections among preterm infants was nonsignificantly higher in the probiotic group compared to the control group. Conclusion: This systematic review shows that the administration of probiotics has moderate preventive or mitigating effects on the occurrence of VAP in ICU patients, CDI, AAD, and nosocomial infections among children. Consequently, applying antibiotics along with the proper probiotic species can be advantageous.

Global prevalence and antibiotic resistance in clinical isolates of Stenotrophomonas maltophilia: a systematic review and meta-analysis.

Introduction: Stenotrophomonas maltophilia is a little-known environmental opportunistic bacterium that can cause broad-spectrum infections. Despite the importance of this bacterium as an emerging drug-resistant opportunistic pathogen, a comprehensive analysis of its prevalence and resistance to antibiotics has not yet been conducted. Methods: A systematic search was performed using four electronic databases (MEDLINE via PubMed, Embase, Scopus, and Web of Science) up to October 2019. Out of 6,770 records, 179 were documented in the current meta-analysis according to our inclusion and exclusion criteria, and 95 studies were enrolled in the meta-analysis. Results: Present analysis revealed that the global pooled prevalence of S. maltophilia was 5.3 % [95% CI, 4.1-6.7%], with a higher prevalence in the Western Pacific Region [10.5%; 95% CI, 5.7-18.6%] and a lower prevalence in the American regions [4.3%; 95% CI, 3.2-5.7%]. Based on our meta-analysis, the highest antibiotic resistance rate was against cefuroxime [99.1%; 95% CI, 97.3-99.7%], while the lowest resistance was correlated with minocycline [4·8%; 95% CI, 2.6-8.8%]. Discussion: The results of this study indicated that the prevalence of S. maltophilia infections has been increasing over time. A comparison of the antibiotic resistance of S. maltophilia before and after 2010 suggested there was an increasing trend in the resistance to some antibiotics, such as tigecycline and ticarcillin-clavulanic acid. However, trimethoprim-sulfamethoxazole is still considered an effective antibiotic for treating S. maltophilia infections.

Pediatric tuberculosis in Iran: a review of 10-years study in an Iranian referral hospital.

INTRODUCTION: Reductions in global tuberculosis incidence are considered as one of the End TB Strategy goal. The diagnosis of tuberculosis (TB) in children is challenging due to insufficient specimen material and the scarcity of bacilli in specimens. The purpose of this study was to evaluate the prevalence, characteristics, clinical profiles, laboratory findings and treatment outcomes of children infected with TB in an Iranian referral hospital during a 10-years period. METHODS: This study was a retrospective analysis of the medical records of 90 children (£15 years) with a diagnosis of tuberculosis who were admitted to Children's Medical Center Hospital, Tehran, Iran, between March 2006 and March 2016. The patients' information such as demographic, clinical manifestations, laboratory, radiological and histological tests results, and treatment outcomes were extracted from medical records and were analyzed. RESULTS: The total prevalence of TB was about 56.6 per 100,000 admitted patients. Most of the patients were between 5 to 12 years. Sixty-one percent were male. Twenty-two percent had the history of TB in their family. Underlying diseases were identified in 30 cases (33%). Thirty-four cases (38%) had pulmonary TB (PTB), 35 cases (39%) had extrapulmonary TB (EPTB), while disseminated TB (DTB) was found in 21 cases (23%). Distribution of DTB in males was higher than in females (36% vs. 6%). In patients < 1 year, DTB was the most frequent type (48 %); however, in patients > 1 year both PTB and EPTB had similar distributions (42%) and were more frequent than DTB (16%).  Conclusions: The total prevalence rate of TB in our study was 56.6 per 100,000 admitted patients. Since the mortality rate was higher in infants, children with DTB and children with underlying diseases, early detection and treatment of these patients will help to reduce the mortality rate of TB disease.

Combinatorial effects of antibiotics and enzymes against dual-species Staphylococcus aureus and Pseudomonas aeruginosa biofilms in the wound-like medium.

Bacterial biofilms are one of the major issues in the treatment of chronic infections such as chronic wounds, where biofilms are typically polymicrobial. The synergy between species can occur during most polymicrobial infections, where antimicrobial resistance enhances as a result. Furthermore, self-produced extracellular polymeric substance (EPS) in biofilms results in a high tolerance to antibiotics that complicates wound healing. Since most antibiotics fail to remove biofilms in chronic infections, new therapeutic modalities may be required. Disruption of EPS is one of the effective approaches for biofilm eradication. Therefore, degradation of EPS using enzymes may result in improved chronic wounds healing. In the current study, we investigated the efficacy of trypsin, ß-glucosidase, and DNase I enzymes on the degradation of dual-species biofilms of Pseudomonas aeruginosa and Staphylococcus aureus in a wound-like medium. These species are the two most common bacteria associated with biofilm formation in chronic wounds. Moreover, the reduction of minimum biofilm eradication concentration (MBEC) of meropenem and amikacin was evaluated when combined with enzymes. The minimum effective concentrations of trypsin, ß-glucosidase, and DNase I enzymes to degrade biofilms were 1 µg/ml, 8 U/ml, and 150 U/ml, respectively. Combination of 0.15 µg/ml trypsin and 50 U/ml DNase I had a significant effect on S. aureus-P. aeruginosa biofilms which resulted in the dispersal and dissolution of all biofilms. In the presence of the enzymatic mixture, MBECs of antibiotics showed a significant decrease (p < 0.05), at least 2.5 fold. We found that trypsin/DNase I mixture can be used as an anti-biofilm agent against dual-species biofilms of S. aureus-P. aeruginosa.

The Causative Organisms of Bacterial Meningitis and their Antimicrobial Resistance Profiles in Iranian Children in 2011-2016.

OBJECTIVES: The study aimed to describe the identity and antimicrobial resistance patterns of the causative agents of bacterial meningitis in children referred to Children's Medical Center (CMC) Hospital, Tehran, Iran. METHODS: This retrospective study was performed at CMC Hospital during a six-year period from 2011 to 2016. The microbiological information of the patients with a diagnosis of bacterial meningitis was collected and the following data were obtained: patients' age, sex, hospital ward, the results of CSF and blood cultures, and antibiotic susceptibility profiles of isolated organisms. RESULTS: A total of 118 patients with bacterial meningitis were admitted to CMC hospital. Sixty-two percent (n=73) of the patients were male. The median age of the patients was ten months (interquartile range [IQR]: 2 months-2 years) and the majority of them (n=92, 80%) were younger than two years of age. The highest number of patients (n=47, 40%) were admitted to the surgery department. Streptococcus epidermidis was the most frequent isolated bacterium (n=27/127, 21%), followed by Klebsiella pneumoniae (n=20/127, 16%), and Staphylococcus aureus (n=16/127, 12.5%). Blood culture was positive in 28% (n=33/118) of patients. Ampicillin-sulbactam and imipenem were the most effective antibiotics against Gram-negative bacteria isolated from CSF cultures. In the case of Gram-positive organisms, ampicillinsulbactam, vancomycin, and linezolid were the best choices. Imipenem was the most active drug against Gram-negative blood pathogens. Also, ampicillin and vancomycin had the best effect on Gram-positive bacteria isolated from blood cultures. CONCLUSION: Results of this study provide valuable information about the antibiotic resistance profiles of the etiologic agents of childhood meningitis, which can be used for prescription of more effective empirical therapies.

Phenotypic and genotypic determinants of mupirocin resistance among Staphylococcus aureus isolates recovered from clinical samples of children: an Iranian hospital-based study.

BACKGROUNDS: The aim of this study was to evaluate both phenotypic and genotypic determinants of mupirocin resistance among methicillin-resistant Staphylococcus aureus (MRSA) and methicillin susceptible S. aureus (MSSA) strains recovered from different clinical samples of children who were admitted to the Children's Medical Center (CMC) Hospital, Tehran, Iran. MATERIALS AND METHODS: A total of 120 clinical isolates of S. aureus were collected from the microbiology laboratory of CMC Hospital. Antimicrobial susceptibility of the isolates to different antimicrobial agents was determined by disk diffusion method. The methicillin resistance phenotype (MRSA) was identified using a 30 µg cefoxitin disk. The minimum inhibitory concentration (MIC) of mupirocin was determined by broth microdilution method. Strains with mupirocin MIC between 8 and 256 µg/mL were considered as low-level mupirocin resistant (LLMR), and strains with an MIC≥512 µg/mL were considered as high-level mupirocin resistant (HLMR). The presence of genes encoding HLMR (ie, mupA and mupB genes) was evaluated by PCR method. RESULTS: Four out of 120 isolates (3%) had mupirocin MIC≥512 µg/mL and were HLMR; however, no LLMR isolate was detected. Fifty-two isolates (43%) were MRSA, and there were no differences in the distribution of mupirocin resistance among MRSA and MSSA isolates (P>0.05). The PCR method identified mupA gene in two out of four HLMR isolates, and mupB gene was not detected in any HLMR isolates. CONCLUSION: Because of discrepancies between the phenotypic and genotypic patterns of mupirocin resistance and due to the avoidance of false-negative results, it is better to determine the mupirocin resistance by both antibiotic susceptibility tests and PCR method. Considering the increasing need of mupirocin for the control of S. aureus infections, continuous checking of its susceptibility status is necessary.

Antibiotic susceptibility of Helicobacter pylori strains isolated from Iranian children: High frequency of A2143G point mutation associated with clarithromycin resistance.

OBJECTIVE: Increasing antibiotic resistance in Helicobacter pylori is a global concern and is associated with treatment failure. The aim of this study was to evaluate antibiotic resistance of H. pylori to different antibiotics including amoxicillin, erythromycin, ciprofloxacin, furazolidone, tetracycline, metronidazole and clarithromycin. In addition, ​detection of A2143G mutation in clarithromycin resistant isolates was performed using real-time PCR technique. METHODS: Ninety patients with upper gastrointestinal symptoms were enrolled in this study. H. pylori were isolated from 32 specimens and the resistance rate of these strains to amoxicillin, erythromycin, ciprofloxacin, furazolidone, and tetracycline was tested by disc agar diffusion method. The resistance level to metronidazole and clarithromycin was determined by agar dilution method. The presence of A2143G point mutation in clarithromycin resistant isolates was determined using real-time PCR technique. RESULTS: The resistance rates to amoxicillin, erythromycin, ciprofloxacin, furazolidone, tetracycline, metronidazole and clarithromycin were 53%, 50%, 37.5%, 62.5%, 25%, 62.5% and 22%, respectively. The A2143G point mutation was detected in 71% of clarithromycin resistant strains (5 out of 7). CONCLUSIONS: The prevalence of H. pylori resistance to metronidazole, ciprofloxacin, erythromycin, amoxicillin and furazolidone in Iran is high. Determination of antibiotic susceptibility plays an important role in selecting of the appropriate anti H. pylori regimen.

Antimicrobial resistance patterns of Gram-negative bacteria isolated from bloodstream infections in an Iranian referral paediatric hospital: A 5.5-year study.

OBJECTIVES: Bloodstream infections (BSIs) are a major cause of paediatric morbidity and mortality worldwide. This study describes the epidemiology and antimicrobial resistance of Gram-negative bacteria (GNB) from BSIs in children admitted to an Iranian paediatric hospital. METHODS: Clinical and microbiological data of patients with positive blood cultures were collected from March 2011 to September 2016. Standard laboratory methods were used for blood culture and bacterial identification. Antimicrobial sensitivity was evaluated by the Kirby-Bauer disk diffusion and broth microdilution methods. RESULTS: Of 2325 bacterial pathogens isolated from blood cultures, 41.1% (n=956) were GNB. Most clinical isolates (n=208; 21.8%) were identified in the cardiac intensive care unit. Predominant bacterial isolates were Klebsiella pneumoniae subsp. pneumoniae (n=263; 27.5%), Escherichia coli (n=192; 20.1%), Serratia marcescens (n=151; 15.8%), Pseudomonas aeruginosa (n=111; 11.6%) and Enterobacter spp. (n=100; 10.5%). Enterobacter isolates showed a high level of ampicillin resistance. Escherichia coli were highly resistant to chloramphenicol (100%), cefixime (100%), ceftriaxone (100%) and ampicillin (96%). Cefixime had the least efficacy against Haemophilus spp. (100% resistant). All K. pneumoniae (100%) were ampicillin-resistant. All S. marcescens were ceftazidime-resistant. No Acinetobacter baumannii were resistant to colistin. All P. aeruginosa were resistant to cefotaxime and trimethoprim/sulfamethoxazole. CONCLUSIONS: These results demonstrate the increasing trend in antibiotic resistance among GNB associated with BSI in children, emphasising the importance of continuous screening and surveillance programmes for detection of antibiotic resistance in BSI pathogens for selection of appropriate treatment regimens.

Monoterpene isolated from the essential oil of Trachyspermum ammi is cytotoxic to multidrug-resistant Pseudomonas aeruginosa and Staphylococcus aureus strains.

INTRODUCTION: The aim of this study was to determine whether an herbal extract containing monoterpene exhibited activity against multidrug-resistant Staphylococcus aureus and Pseudomonas aeruginosa isolated from clinical infection samples. METHODS: The essential oil of Trachyspermum ammi (L.) Sprague ex Turrill (Apiaceae) fruit was extracted by hydrodistillation. Fruit residues were treated with hydrochloric acid and re-hydrodistilled to obtain volatile compounds. Compounds in the distilled oil were identified using gas-chromatography (GC) and GC-mass spectrometry (MS). The antibiotic susceptibility of all bacterial isolates was analyzed using both the disc diffusion method and determination of the minimum inhibitory concentration (MIC). The sensitivity of antibiotic-resistant isolates to essential oil was also determined by using the disc diffusion method and MIC determination. RESULTS: Of 26 clinical isolates, 92% were multidrug-resistant (MDR). Aromatic monoterpenes (thymol, paracymene, and gamma-terpinene) were the major (90%) components of the oil. Growth of S. aureus strains was successfully inhibited by the oil, with an inhibitory zone diameter (IZD) between 30-60mm and MIC <0.02µL/mL. The oil had no antimicrobial activity against clinical isolates of P. aeruginosa; rather, it prevented pigment production in these isolates. CONCLUSIONS: This study revealed that the essential oil of Trachyspermum ammi, which contains monoterpene, has good antibacterial potency. Monoterpenes could thus be incorporated into antimicrobial ointment formulas in order to treat highly drug-resistant S. aureus infections. Our findings also underscore the utility of research on natural products in order to combat bacterial multidrug resistance.

Evaluation of Mannosidase and Trypsin Enzymes Effects on Biofilm Production of Pseudomonas aeruginosa Isolated from Burn Wound Infections.

Biofilm is an important virulence factor in Pseudomonas aeruginosa and has a substantial role in antibiotic resistance and chronic burn wound infections. New therapeutic agents against P. aeruginosa, degrading biofilms in burn wounds and improving the efficacy of current antimicrobial agents, are required. In this study, the effects of α-mannosidase, ß-mannosidase and trypsin enzymes on the degradation of P. aeruginosa biofilms and on the reduction of ceftazidime minimum biofilm eliminating concentrations (MBEC) were evaluated. All tested enzymes, destroyed the biofilms and reduced the ceftazidime MBECs. However, only trypsin had no cytotoxic effect on A-431 human epidermoid carcinoma cell lines. In conclusion, since trypsin had better features than mannosidase enzymes, it can be a promising agent in combatting P. aeruginosa burn wound infections.

Monoterpene isolated from the essential oil of Trachyspermum ammi is cytotoxic to multidrug-resistant Pseudomonas aeruginosa and Staphylococcus aureus strains

Abstract INTRODUCTION: The aim of this study was to determine whether an herbal extract containing monoterpene exhibited activity against multidrug-resistant Staphylococcus aureus and Pseudomonas aeruginosa isolated from clinical infection samples. METHODS: The essential oil of Trachyspermum ammi (L.) Sprague ex Turrill (Apiaceae) fruit was extracted by hydrodistillation. Fruit residues were treated with hydrochloric acid and re-hydrodistilled to obtain volatile compounds. Compounds in the distilled oil were identified using gas-chromatography (GC) and GC-mass spectrometry (MS). The antibiotic susceptibility of all bacterial isolates was analyzed using both the disc diffusion method and determination of the minimum inhibitory concentration (MIC). The sensitivity of antibiotic-resistant isolates to essential oil was also determined by using the disc diffusion method and MIC determination. RESULTS: Of 26 clinical isolates, 92% were multidrug-resistant (MDR). Aromatic monoterpenes (thymol, paracymene, and gamma-terpinene) were the major (90%) components of the oil. Growth of S. aureus strains was successfully inhibited by the oil, with an inhibitory zone diameter (IZD) between 30-60mm and MIC <0.02μL/mL. The oil had no antimicrobial activity against clinical isolates of P. aeruginosa; rather, it prevented pigment production in these isolates. CONCLUSIONS: This study revealed that the essential oil of Trachyspermum ammi, which contains monoterpene, has good antibacterial potency. Monoterpenes could thus be incorporated into antimicrobial ointment formulas in order to treat highly drug-resistant S. aureus infections. Our findings also underscore the utility of research on natural products in order to combat bacterial multidrug resistance.