Genotypic detection of rifampicin-resistant M. tuberculosis strains in Syrian and Lebanese patients

SummarySettingThe incidence of multi- and extensively drug-resistant TB cases is increasing in many countries. Resistance to rifampicin is widely considered a surrogate marker for multiple drug resistant TB. No efforts have been made to identify and quantify the drug-resistant genotypes in the Syrian and Lebanese communities.ObjectiveThe genotypic characterization of rpo B mutations in the rifampicin drug-resistance region (RRDR) of resistant Mycobacterium tuberculosis isolates in Syrian and Lebanese patients.DesignThe pyrosequencing technique was applied to DNA derived from the M. tuberculosis isolates of 56 patients.ResultsRRDR sequencing identified 97 modified codons representing 35 different mutations; 31 (34%) of the 97 modifications were novel and have not been previously reported. The changes were mostly within codons 531 (37/97: 38%), 533 (28/97: 29%) and 526 (9/97: 9%). Additionally, 30 (54%) isolates had multiple codon changes.ConclusionThis study indicates the importance of the RRDR hotspot region for the detection of rifampicin resistance in MTB clinical isolates from Syrian and Lebanese patients. However, new mutations and mutations in other locations within the RRDR were also observed. The vast majority (95%) of the studied isolates from this pool of patients contained mutations in codons 531 and/or 533

Molecular Characterization and resistance of H. influenzae isolated from Nasopharynx of Students in North Lebanon

Introduction: Haemophilus influenzae is an important cause of respiratory infections,including acute otitis media, sinusitis, and chronic bronchitis, which arepreceded by asymptomatic H. influenzae colonization of the human pharynx. Theaim of this study is to investigate the rate of H.influenzae nasopharyngeal colonizationamong students ages 2 to 3 years.Material and methods: A total of 21 isolates of clinical H. influenzae wereisolated from 87 nasopharyngeal specimens of children between April and June2011. The isolates were identified by using molecular techniques (PCR), biotypeswere determined by using the following tests: ornithin decarboxylase, urease andtryptophanase, and capsular typing was performed by SAST by using polyclonaland specific b antisera (Difco-BD®-USA).The prevalence of β -lactams resistance, β-lactamase production, the level of macrolideresistance was recorded for each strain by using disc diffusion and E-teststrip methods and chromogenic cephalosporin test (cefinase). β -lactams resistancegenes (blaTEM and blaROB) were determined using PCR.Results: 42.8 % of the H. influenzae isolates were type b, and biotypes I, II andIII were the majority, whereas biotypes IV, VI and VIII was not found. The majorityof capsule type b was belonged to biotype II. Antibiotics susceptibility showedthat 19% of the isolates were resistant to ampicillin and produced type TEM-1β-lactamase.Conclusion: This study shows the carriage rate of H. influenzae in North Lebanonchildren. The incidence of resistance rate of 19% to ampicillin signals an importantwarning to the future prophylaxis use of beta-lactam in treatment of H. influenzaeinfections in Lebanon

Detection of Escherichia coli O157:H7 and O104:H4 in patients with diarrhea in Northern Lebanon and characterization of fecal E.coli producing ESBL and carbapenemase genes

Background. While most strains of Escherichia coli (E. coli) are harmless, some are causing intestinal infections of varying severity. Then Shiga toxin-producing E. coli (STEC)/ enterohemorrhagic E. coli strains can be associated with fatal clinical manifestations. Of these E. coli Serotypes O157: H7 and O104: H4 were responsible for worldwide epidemics causing thousands of intestinal infections and dozens of deaths.The aim of this research is to investigate the prevalence of E. coli O157: H7 and O104: H4 in the diarrheal stools of 242 Lebanese patients.Materials and methods. This study includes 242 E. coli strains isolatedfrom fecal specimens of patients with diarrhea between February2013 and May 2014 in the microbiology department of Nini HospitalLaboratory in Tripoli - North Lebanon. All specimens were inoculatedon sorbitol MacConkey agar. Sorbitol negative strains were investigated for detection of stx1, stx2 and eae genes using real-time PCR. All carbapenem-resistant strains and ESBL producers were investigated by PCR for presence of KPC, IMI, NMC-A, EMS, GHG, VIM, NDM, IMP,OXA-48, blaTEM, blaCTX-M, blaSHV, blaOXA, blaGES and blaPER..Results. A total of 14 sorbitol negative strains were detected. The search for stx1, stx2 and eae genes showed the presence of a single positive strain for E. coli O157: H7. Out of 242 E.coli strains, 48 (19.8%) were ESBL-positive, 4 (1.6%) were resistant to ertapenem, and all were negative for stx2 genes, The blaCTX-M gene was the most frequentamong ESBL positive strains (85%), followed by the blaTEM gene (50%). One strain had the blaNDM-1 gene, another had the blaOXA-48 gene and 2 strains were probably resistant due to impermeability.Conclusion. The results of this study demonstrate rarely presence of enterohemorrhagic E. coli, but shows the frequent presence of multidrug resistant E.coli in the intestinal flra of North Lebanese patients. Therefore, it is important to search for MDR E.coli in the intestinal flra of patients who are going to be treated with major operations or those admitted to intensive care unit

Detection of genes TEM, OXA, SHV and CTX-M in 73 clinical isolates of Escherichia coli producers of extended spectrum Betalactamases and determination of their susceptibility to antibiotics.

A total of 73 clinical isolates of extended spectrum β- lactamase producingEscherichia coli were sampled in North Lebanon

Characterization of Cephalosporinases Produced by Clinical Isolates of Enterobacteriacae in North Lebanon

Background: The problem of Enterobacteriacae resistance to β-Lactamase drugsis of growing concern in hospitals. Enterobacteria have developed multiple mechanismsof resistance to antibiotics, the main one is the enzymatic resistance mediatedby the beta-lactamases. This study aims to characterize the occurrence ofcephalosporinases in clinical isolates of Enterobacteriacae isolates in North Lebanon.Methods. Twenty two strains of Enterobacteriacae producing high level of cephalosporinaseshave been studied. The antibiotic susceptibility of each strain wastested on Mueller Hinton agar contains cloxacilline (250 mg/L) and by using E-testaccording the guidelines of the Antibiogram Committee of the French Society forMicrobiology. The search for plasmid-mediated cephalosporinases was performedusing PCR and primers for plasmid-mediated cephalosporinases genes (CMY-2,DHA-1, ACT-1, ACC-1, FOX-1 and MOX-1).Results: Thirteen positive strains were detected, of these 9 strains produced theplasmid-mediated cephalosporinase (CMY-2) and one strain produced the plasmidmediatedcephalosporinase (DHA-1). The remaining 9 strains were high-level chromosomalcephalosporinase producers since they belong to group-three Enterobacteria.They did neither produce plasmid-mediated cephalosporinase, nor did theyhave resistance to third generation cephalosporins except for cefepim. Two strains(CMUL E. coli 021) and CMUL E. coli 255) which were not susceptible for cefepim byE-test produced plasmid-mediated cephalosporinase The sequencing result of these2 E.coli strains did not show any mutation in the promoter that is responsible forhigh expression level of the chromosomal cephalosporinase. All examined strainsproducing plasmid-mediated cephalosporinase CMY-2 were analyzed by ERIC-PCRtechnique. The results showed that two of these strains had the same pattern (C4and C5) and three others had another pattern (C10, C12 and C13).Conclusion: This study shows the variations of cephalosporinases produced byclinical isolates of Enterobacteriacae in North Lebanon

Identification of Novel Functions for Hepatitis C Virus Envelope Glycoprotein E1 in Virus Entry and Assembly

International audienceHepatitis C virus (HCV) envelope glycoprotein complex is composed of E1 and E2 subunits. E2 is the receptor-binding protein as well as the major target of neutralizing antibodies, whereas the functions of E1 remain poorly defined. Here, we took advantage of the recently published structure of the N-terminal region of the E1 ectodomain to interrogate the functions of this glycoprotein by mutating residues within this 79-amino-acid region in the context of an infectious clone. The phenotypes of the mutants were characterized to determine the effects of the mutations on virus entry, replication, and assembly. Furthermore, biochemical approaches were also used to characterize the folding and assembly of E1E2 heterodimers. Thirteen out of 19 mutations led to viral attenuation or inactivation. Interestingly, two attenuated mutants, T213A and I262A, were less dependent on claudin-1 for cellular entry in Huh-7 cells. Instead, these viruses relied on claudin-6, indicating a shift in receptor dependence for these two mutants in the target cell line. An unexpected phenotype was also observed for mutant D263A which was no longer infectious but still showed a good level of core protein secretion. Furthermore, genomic RNA was absent from these noninfectious viral particles, indicating that the D263A mutation leads to the assembly and release of viral particles devoid of genomic RNA. Finally, a change in subcellular colocalization between HCV RNA and E1 was observed for the D263A mutant. This unique observation highlights for the first time cross talk between HCV glycoprotein E1 and the genomic RNA during HCV morphogenesis

Characterization of resistance genes to macrolides, lincosamides and streptogramins (MLS) among clinical isolates of Staphylococcus aureus in North Lebanon

Background. – Staphylococcus aureus is one of the most significant pathogens causing significant morbidity and mortality. Moreover, the incidence of MLS-resistant Staphylococcus aureus infections continues to grow globally.Objective. – The aim of this study is to examine the expression of resistance of Staphylococcus aureus (S. aureus) isolates to MLS and the prevalence of genes involved in this resistance by PCR.Methods. – 38 strains of S. aureus MLS-resistant (resistant at least for one macrolide) were isolated in the sector of microbiology at Nini Hospital in North Lebanon. The disk diffusion method was used to determine the phenotype of the MLS resistance. The resistance genes involved were detected by PCR using specific gene primers for ermA, ermB, ermC, msrA, linA, mefA, vat and vgb genes.Results. – A total of 55.3% of the isolates were positive for inducible phenotype (iMLSB), 15.8% for the constitutive phenotype (cMLSB), 23.7% for MSB phenotype and 5.2% for L phenotype. The ermC gene was the most prevalent (52.6%), while ermA, ermB, msrA and linA genes were observed with lower prevalence. However, a combination of several of these genes was detected. The vgb, vat and mefA genes were not detected in any of the clinical isolates.Conclusion. – To our knowledge, this study is the first investigation regarding characterization of MLS resistance genes in clinical isolates of S. aureus in Lebanon. The study revealed a high prevalence of the inducible resistance to lincosamides (iMLSB phenotype) and the most prevalent resistance determinants was ermC

Parasitic Contamination of Fresh Leafy Green Vegetables Sold in Northern Lebanon

Contaminated, raw or undercooked vegetables can transmit parasitic infections. Here, we investigated parasitic contamination of leafy green vegetables sold in local markets in the Tripoli district, Lebanon, during two consecutive autumn seasons (2020–2021). The study involved the microscopic examination of 300 samples of five different types of vegetables (60 samples per type) and used standardized qualitative parasitological techniques for some protozoa and helminths. The results showed that 16.7% (95% interval for p: 12.6%, 21.4%) (50/300) of the vegetable samples were contaminated with at least one parasite. The most frequently detected parasite was Blastocystis spp. (8.7%; 26/300); this was followed in frequency by Ascaris spp. (3.7%; 11/300). Among the different vegetable types, lettuce (23.3%; 14/60) was the most contaminated, while arugula was the least contaminated (11.7%; 7/60). The statistical analysis did not reveal any significant association between the prevalence of parasitic contamination and the investigated risk factors, which included collection date, vegetable type, market storage status, and wetness of vegetables at the time of purchase (p > 0.05). The high prevalence of parasitic contamination also suggested the potential presence of other microbial pathogens. These findings are important because leafy green vegetables are preferentially and heavily consumed raw in Lebanon. Thus, implementing effective measures that target the farm-to-fork continuum is recommended in order to reduce the spread of intestinal pathogens

Identification of the first bacteriocin isolated in Lebanon extracted via a modified adsorption-desorption method and its potential food application

Introduction: The raw goat milk is considered as a good source of novel bacteriocinogenic lactic acid bacteria (LAB) strains. Method: The bacteriocin, which named enterocin CMUL20-2 was secreted by Enterococcus faecium CMUL20-2. This bacterial strain was originally isolated from raw goat’s milk, was extracted by using a modified adsorption-desorption method and purified via RP-HPLC. antimicrobial activity was tested against several pathogenic and spoilage microbes. Results: The enterocin CMUL20-2 showed a strong adsorption on cell wall of producer strain even in acidic environment which facilitate its extraction in only two simple steps. The recovered purified enterocin has decreased procedure time and diminished the number of undesirable molecules present in Rogosa and Sharpe (MRS) broth. The recovered enterocin showed antimicrobial activity against several foodborne pathogenic and spoilage microbes. Conclusion:  The recovered enterocin was able to tolerate a variety of food chain conditions such as high temperature, pH and storage stability, and it can be a good candidate to protect food from spoilage microbes &nbsp

Current molecular methods in epidemiological typing of Acinetobacter baumannii

International audienc