Antimicrobial activity of Cinnamomum zeylanicum essential oil against colistin-resistant gram-negative bacteria.

In the current study, we evaluated the antimicrobial activity of Cinnamomum zeylanicum Blume essential oil (Cinn-EO) against a group of thirteen clinical colistin-resistant Gram-negative bacteria, including Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The GCMS analysis showed that cinnamaldehyde was the major compound (94.29%) of the Cinn-EO. The diameter of the inhibition zone by Cinn-EO varied from 24 to 37 mm. The minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values ranged between 0.625 and 5 mg/mL. Interestingly, the MBC/MIC was equal to 1 for most tested bacterial strains, indicating an advanced bactericidal effect of Cinn-EO against colistin-resistant Gram-negative bacteria. The absorption, distribution, metabolism, elimination, and toxicity (ADMET) prediction showed good pharmacokinetic properties of the tested cinnamaldehyde. The results suggest that cinnamaldehyde could be a potential alternative to treat infection caused by colistin-resistant Gram-negative bacteria.

Synergistic activity of Thymus capitatus essential oil and cefotaxime against ESBL-producing Klebsiella pneumoniae.

The objective of the current study was to evaluate the interaction between Tunisian Thymus capitatus essential oil (EO) and cefotaxime against Extended-Spectrum Beta-lactamases (ESBLs) producing Klebsiella pneumoniae hospital strains. GC-MS revealed that the major component of EO was found to be carvacrol (69.28%). The EO exerts an advanced bactericidal effect against all strains. Synergy between EO and cefotaxime was obtained by combined disk diffusion and checkerboard techniques. Combined use of EO and cefotaxime reduced the MIC of imipenem by 8- to 128-fold for all strains (fractional inhibitory concentration index ˂ 0.5, synergy). The time kill curve assay confirmed the advanced activity of combinatory effects of EO and cefotaxime, with total reduce of bacterial number (CFU/mL) after 6 h of culture. Synergistic activity of the combination between EO and cefotaxime constitute an important strategy as therapeutical option to combat infections caused by ESBLs producing Klebsiella pneumoniae.

Pooling Nasopharyngeal Swab Specimens to Improve Testing Capacity for SARS-CoV-2 by Real-Time RT-PCR.

BACKGROUND: The detection of SARS-CoV-2 using qRT-PCR with the pooling of samples can reduce workload and costs especially when the prevalence rate of COVID-19 in a population is low. To analyse the effect of pooling samples on the sensitivity of RT-qPCR for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection, we compared the cycle threshold (Ct) values of pools of 5 and 10 that tested positive with Ct values of individual samples that tested positive in that pool. Twenty positive nasopharyngeal (NP) specimens with low to high viral load were selected and pooled individually with four and nine negative NP. RESULTS: In NP specimens, the sensitivity of pools of 5 and 10 were 90 and 85%, compared to individual sample testing, respectively. The RT-qPCR sensitivity of pools of 5 and 10 against individual testing were not significantly different (p > 0.05). Detection of positive samples with low Ct values (< 36) was consistently achieved in pools of 5 and 10. However, there were higher false negatives when samples with high ct values (> 36) were pooled and tested. The mean Ct values obtained with the 5-sample pooled testing exceeded individual sample testing by 1.85 ± 1.09 cycles, while Ct values obtained with the 10-sample pooling exceeded individual sample testing by 3.4 ± 1.65 cycles. CONCLUSIONS: In a low prevalence setting, testing capacity can be increased by pooling 5 or 10 samples, but the risk of additional false negatives needs to be considered.

Association of an IFN-γ variant with susceptibility to chronic hepatitis B by the enhancement of HBV DNA replication.

Interferon gamma (IFN-γ) is a crucial cytokine in host immune response to hepatitis B virus (HBV) infection. This study aimed to determine whether a functional polymorphism +874T/A in IFN-γ gene linked to high and low producer phenotypes [IFN-γ (+874Thigh â†’ Alow)] may alter the outcomes of chronic HBV infection in Tunisian population. The +874T/A was analysed by ARMS-PCR method in the group of 200 patients chronically infected with HBV and 200 healthy controls. We observed that minor +874A allele, minor +874AA and +874TA genotypes were significantly more frequent in the chronic hepatitis B group in comparison to the control group [49 vs. 31%, P < 10-4; 24 vs. 13%, P < 10-4; 52 vs. 38%, P < 10-4; respectively]. Besides, they were associated with susceptibility to hepatitis B infection [OR = 2.15, 3.87 and 2.84, respectively]. The minor +874A allele and +874AA genotype were statistically more representative in the sub-group of patients with high viral DNA load when compared with the sub-group of patients with low HBV DNA load [(57% vs. 43%, P = 0.003, OR = 1.79); (33% vs. 14%, P = 0.003, OR = 3.59), respectively]. Collectively, our study suggests an association between the IFN-γ +874T/A SNP and persistence of HBV by the enhancement of HBV DNA replication.

Virulence of clinically relevant multidrug resistant Corynebacterium striatum strains and their ability to adhere to human epithelial cells and inert surfaces.

Corynebacterium striatum is a nosocomial pathogen which is increasingly associated with serious infections in both immunocompetent and immunocompromised patients. However, little is known about virulence factors and mechanisms that may enhance the establishment and long-term survival of Corynebacterium striatum. in the hospital environment. In this study, we investigated the ability of 22 multidrug-resistant C. striatum clinical isolates to adhere to human epithelial cells and to produce biofilm on polystyrene plates, glass and various tracheostomy tubes. We also tested the virulence of these strains on the nematode Caenorhabditis elegans. They showed good adhesion to epithelial human cells after 180 min of infection. The 22 C. striatum were able to produce biofilms on positively and negatively charged abiotic surfaces at 37 °C. They were also able to infect and to kill Caenorhabditis elegans after 5 days of infection. The virulence condition was associated with the presence of SpaDEF operon encoding pili in all strains. This study provides new insights on virulence mechanisms that may contribute to the persistence of C. striatum in the hospital environment, increasing the probability of causing nosocomial infections.

Co-infections of human herpesviruses (CMV, HHV-6, HHV-7 and EBV) in non-transplant acute leukemia patients undergoing chemotherapy.

BACKGROUND: Human herpesviruses (HHVs) remain latent after primary infection and can be reactivated in response to immunosuppression and chemotherapy. Little is known about their incidence, potential relationships, risk factors and clinical impact in non-transplant leukemia patients. This study investigated prospectively incidence, risk factors, clinical impact and possible association of HHVs-(1-7) infections in patients with newly diagnosed acute leukemia. METHODS: Study design involved longitudinal sampling before chemotherapy and in different phases of chemotherapy: post-induction, post-remission, and post-salvage during 2016-2018. A total of 734 plasma samples from 95 patients were analyzed by a qualitative, multiplex PCR for HHVs detection and a quantitative real-time PCR was used for cytomegalovirus (CMV) quantification. HHVs-(1-6) IgG and IgM antibodies were tested using immunoassays. Risk factors were analyzed by binary logistic regression and relationships between viruses were analyzed using the Chi-square or Fisher's exact test as appropriate. RESULTS: The overall seroprevalences of HHV-(1-6) IgG were high (> 80%). At least one herpes viral agent was detected in 60 patients (63.3%). CMV was the most commonly detected virus in the different phases of chemotherapy (19.4%), followed by HHV-6 (9.7%), HHV-7 (5.2%) and EBV (2.7%). HSV-1/2 and VZV DNA were not detected. Twenty-seven patients (28.4%) had more than one virus detected in the follow-up, with 23 who were co-infected. CMV/HHV-6 was the most frequent co-infection (69.5%, 16/23). HHV-6 infection (p = 0.008) was identified as a risk factor for CMV infection while salvage treatment (p = 0.04) and CMV infection (p = 0.007) were found to be independent risk factors for HHV-6 infection. CMV co-infection was associated with severe lymphopenia with an absolute lymphocyte count (ALC) (< 500/µL) (p = 0.009), rash (p = 0.011), pneumonia (p = 0.016) and opportunistic infections [bacteremia, p < 0.001 and invasive fungal infection, (p = 0.024)] more frequently than CMV mono-viral infections. CONCLUSIONS: Our data suggest that co-infection with HHVs, especially CMV and HHV-6, may contribute to the development of serious clinical manifestations with profound lymphopenia, pneumonia rash and increased risk for bacterial and fungal co-infections. These findings may suggest the synergistic effect of HHVs associated infection.

Demographic and seasonal characteristics of respiratory pathogens in neonates and infants aged 0 to 12 months in the Central-East region of Tunisia.

BACKGROUND: This study aimed to characterize the epidemiology of pathogenic respiratory agents in patients aged 0 to 12 months and hospitalized for acute respiratory infections in Tunisia between 2013 and 2014. METHODS: A total of 20 pathogens, including viruses, Mycoplasma pneumoniae, and Streptococcus pneumoniae, were detected using molecular sensitive assays, and their associations with the patient's demographic data and season were analyzed. RESULTS: Viral infectious agents were found in 449 (87.2%) of 515 specimens. Dual and multiple infectious agents were detected in 31.4% and 18.6% of the samples, respectively. Viral infection was predominant in the pediatric environment (90.8%, P < 0.001), male patients (88.0%), and spring (93.8%). Rhinovirus was the most detected virus (51.8%) followed by respiratory syncytial virus A/B (34.4%), coronavirus group (18.5%), adenovirus (17.9%), and parainfluenza viruses 1-4 (10.9%). Respiratory Syncytial virus A/B was significantly associated with gender (38.0% male cases vs 28.3% female cases, P = 0.02). Infections by Adenovirus, Bocavirus, and Metapneumovirus A/B increased with increasing age of patients (predominated cases aged 6-12 months, P < 0.001). S. pneumoniae was detected in 30.9% of th tested samples. In 18.2% of the negative viral infections, only S. pneumoniae was identified. CONCLUSION: A predominance of the rhinovirus infection was observed in this study. Coronavirus subtypes were described for the first time in Tunisia. The observed different pathogenic profiles across age groups could be helpful to avoid the misclassification of patients presenting with ARIs at the triage level when no standardized protocol is available. This study will provide clues for physicians informing decisions regarding preventive strategies and medication in Tunisia.

Aeromonas spp. Human Infection: Retrospective Study in the region of Sousse, 2011 - 2015.

OBJECTIVE: To present the clinical and bacteriological characteristics of human Aeromonas infections in the central region of Tunisia from January 2011 to September 2015. METHODS: Retrospective study concerning all Aeromonas spp strains isolated at our laboratory during a period of 5 years (2011-2015). Following data were collected: gender, age, hospital department, co-morbidities, site of infection, date, the Aeromonas species and susceptibility phenotype. Identification was based on conventional criteria and antibiotic susceptibility was performed according to the recommendations of "the Committee of the French Society of Microbiology. RESULTS: Thirty six strains of Aeromonas spp were collected during our study period. Mean age was 24 years old with a sex ratio of 1.1. The samples mainly provided from internal medicine (30,5%), neonatology (19,4%). Digestive tract (33%), blood stream (33%), skin and soft tissues (17%) and urinary tract (3%) were the sites of infection. Five infections (14%) were nosocomial, associated with biomaterials. The quart of patients was immuno-compromised. The seasonal distribution showed a summer-autumn peak. We noted 2 species: A. hydrophila (83%) and A. veronii biovar sobria (17%). All strains were resistant to amoxicillin and amoxicillin-clavulanic acid whereas we noted effectiveness of third-generation cephalosporins (C3G), fluoroquinolones and aminoglycosids.All patients received antibiotic treatment: 93% an association. Four deaths occured not directly linked to Aeromonas infection. CONCLUSION: In our area, Aeromonas infections must be mentioned in case of diarrhea, especially during summer-autumn or sepsis particularly in immunocompromised patients.  A. hydrophila remains the most frequent species at our patients. Due to their resistance to aminopenicillins, a probabilistic treatment including either a fluoroquinolone or a C3G, evently associated with an aminoglycoside, should be conducted.

A new IgG immunoblot kit for diagnosis of toxoplasmosis in pregnant women.

The determination of the accurate immune status of pregnant women is crucial in order to prevent congenital toxoplasmosis. Equivocal results with conventional serological techniques are not uncommon when IgG titers are close to the cut-off value of the test, so that a confirmatory technique is needed. For this purpose, we developed a homemade immunoblot (IB) using soluble extract of Toxoplasma gondii tachyzoites and assessed it by testing 154 positive, 100 negative, and 123 equivocal sera obtained from pregnant women. In order to select the more valuable bands in terms of sensitivity and specificity, we used the Youden Index (YI). The highest YIs were those given by the 32, 36, 98, 21, and 33 bands. The simultaneous presence on the same blot of at least 3 bands showed a much higher YI (0.964) and was adapted as the positivity criterion. The analysis of results showed that our homemade IB correlated well with the commercial LDBIO Toxo II IgG® kit recently recommended as a confirmatory test (96.7% of concordance).

Factors influencing bacterial colonization of double J ureteral stents: a prospective study.

Background: To investigate the microorganisms responsible for double J stent (DJS) colonization, bacteriuria, and the drug susceptibility of the isolates. We also tried to determine factors associated with stent colonization, such as indwelling time, sex, age, and comorbidities. Materials and methods: This study is a prospective analysis of patients following DJS ablation. A total of 155 patients from our institution were enrolled in this study between January 2023 and May 2023. Bladder urine was collected in a sterile container prior to stent removal for bacteriological exam. The removed stents were divided into three parts: top (Renal), middle (Ureteral), and bottom (Bladder); 3 cm pieces from each part were taken and placed in a sterile test tube for bacteriological investigation. Results: The mean age of patients with positive stent culture was 61.17±12.82 versus 55.94±10.32 when stent culture is negative, which is statistically significant P=0.016. Diabetes and bacteriuria are both correlated with DJS contamination with P<0.001 in the two cases. The mean duration of the use of DJS in patients with colonized stent culture is 6.45±2.98 months versus 4.06±2.20 months for the other patients; the difference is statistically significant P<0.001. The most commonly isolated pathogens on stents were Gram-negative bacilli (53.2%), dominated by Enterobacteriaceae in 19 cases (55.2%). Conclusion: Indwelling time is the only unanimous factor of stent colonization in literature, so we recommend using DJS only if necessary and to remove it as soon as possible.

Association of HLA-G 3'UTR polymorphisms with hepatitis B virus infection in Tunisian population.

Hepatitis B virus (HBV) infection is a major public health burden. The mechanisms of immune evasion during chronic HBV (CHB) infection are poorly understood. Human leukocyte antigen (HLA)-G, an immune checkpoint molecule, plays a crucial role in the tolerance mechanisms of various infectious diseases. The 3' untranslated region (3'UTR), including the HLA-G + 3142 C > G polymorphism (rs1063320) and the 14-pb Ins/Del (rs66554220) has been strongly suggested to influence HLA-G expression. This study conducted a case-control analysis to evaluate the potential correlation between the HLA-G + 3142 C > G polymorphism and HBV infection outcome in a Tunisian cohort. The HLA-G + 3142 C > G polymorphism was analysed by PCR-RFLP in 242 patients with chronic HBV infection (116 males and 126 females), 241 healthy controls (116 males and 125 females), and 100 spontaneously resolved subjects (52 males and 48 females). Patients with chronic HBV infection showed a higher frequency of the + 3142G allele compared to healthy controls and spontaneously resolved subjects (p = 0.001 and p = 0.002, respectively). An association between the + 3142G allele and high HBV DNA levels was observed when HBV patients were stratified based on their HBV DNA levels (p = 0.016). Furthermore, the dominant model (GG + GC vs CC) was associated with liver function parameters, including AST, ALT, and high HBV DNA levels (p = 0.04, p < 0.001 and p = 0.002, respectively). However, there was no significant association found between this polymorphism and the fibrosis stage (p = 0.32). The haplotype analysis, using a subset of previously published data on the HLA-G 14-pb Ins/Del polymorphism, revealed an association between the Ins/G haplotype and chronic HBV infection (H1: InsG, p < 0.001). Our findings suggest that the + 3142G allele is a risk factor for the persistence and progression of HBV infection, while the + 3142C allele serves as a protective allele associated with the spontaneous resolution of the infection. Additionally, the HLA-G 3'UTR haplotype Ins/G is associated with chronic HBV infection in the Tunisian population.

[Comparative study of antibiotic resistance in bacteria isolated from burned patients during two periods (2005-2008, 2008-2011) and in two hospitals (Hospital Aziza Othmana, Trauma and Burn Center)]. / Etude comparative de la résistance aux antibiotiques des principales bactéries isolées au service de Réanimation de brûlés durant deux périodes (2005-2008, 2008-2011) et dans deux structures hospitalières (Hôpital Aziza Othmana, Centre de traumatologie et grands brules ben Arous.

BACKGROUND: Continuous monitoring of the bacterial flora and antibiotic resistance of the main bacteria involved in nosocomial infections helps improve treatment and prevention strategies. AIM: To compare the bacteriological profile and antibiotic susceptibility of the main bacterial isolates within the burned patients over two periods of 3 years and in two hospitals. METHODS: During two three-year periods: period 1 (P1): 1/7/2005-30/6/2008 and period 2 (P2): 1/7/2008-30/6/2011) and in two hospitals: Hospital Aziza Othmana (HAO) and the traumatology and burn center (CTGB), 2153 and 3719 non-repetitive strains were isolated from burn patients from different samples. The transfer of the intensive care unit was made on 01/07/2008 from the Hospital Aziza Othmana to CTGB. The study of antibiotic sensitivity was performed according to CA-SFM. RESULTS: During the period P1, Pseudomonas aeruginosa was the main bacteria isolated (18%) followed by Staphylococcus aureus (14%) and Acinetobacter baumannii (12%). After the transfer of intensive care burn unit to the traumatology center, ecology bacterial varied with S. aureus (20%) in the first place followed by P. aeruginosa (15%) and Proteus mirabilis (11%). The study of the evolution of antibiotic susceptibility showed an overall downward trend of resistance in the second half of 2008, immediately after the transfer of service in the new hospital structure. The rate of ceftazidim resistant Klebsilella pneumoniae decreased from 80.4% to 50%, Similarly the resistance of P. aeruginosa to ceftazidime and imipenem decreased respectively from 61% to 39.4% and from 63.3% to 37.1%. Nevertheless, the reduction of resistance was followed by a rapid increasing during the year 2009 to reach overall rates of resistance previously observed in the hospital Aziza Othmana. Concerning S. aureus, the rate of MRSA (methicillin-resistant S. aureus) showed no significant variation throughout the study period: 60% versus 56.3% at HAO and CTGB. A. baumannii brings up the problem of mutirésistance: 92.7% of strains were resistant to ceftazidime and 63.9% to imipenem during P1 with an emphasis on resistance to imipenem during P2 increased to 89.3%. CONCLUSION: Resistance is a problem in the intensive care burn unit. Preventive measures have to be taken.

Human herpesvirus-8 infection in Tunisian adult acute leukemia patients.

Background: Human herpesvirus 8 (HHV-8) has been linked to the development of Kaposi's sarcoma (KS)and multiple other hematologic malignant disorders. However, the role of HHV-8 in acute leukemia patients is unknown. Objectives: The objective of this study was to determine the prevalence of HHV-8 in Tunisian acute leukemia patients and in healthy blood donors. Methods: An indirect immunofluorescence test was used to detect the presence of anti-HHV8 antibodies. Nested PCR was used for the detection of HHV-8 DNAemia in samples of plasma. Results: The seroprevalence of HHV-8 was significantly higher in acute leukemia patients (21,4% ,15/70) than in healthy blood donors (7,1%, 5/70), (p= 0.02). Gender, type of disease, status of disease, prior blood transfusion, and outcome were not associated with HHV-8 seroprevalence. However, among acute leukemia patients, HHV-8 seroprevalence was statistically associated with older age > 40 years of age, (p=0.002). HHV-8 DNAemia was detected (1,4%) in only one patient of acute myeloid leukemia (AML) and none of the healthy blood donors. Conclusions: The seroprevalence of HHV-8 infection in Tunisian adult acute leukemia patients was three times as high compared to healthy blood donors, suggesting that patients with acute leukemia might be at increased risk of HHV-8 infection.

Analysis of Pathogens of Urinary Tract Infections Associated with Indwelling Double-J Stents and Their Susceptibility to Globularia alypum.

Ureteral double-J stents are frequently used to prevent urinary obstruction. They can develop bacterial colonization and encrustation, which leads to persistent infections that seldom respond to antibiotic treatment. Thus, the goal of this study was to evaluate the local spectrum of bacterial pathogens and their susceptibility to natural compounds. A total of 59 double-J ureteral stents from 59 consecutive patients were examined. The samples were inoculated on agar culture mediums. Extracts of Globularia alypum L. were evaluated for their antibacterial activity with the diffusion and broth dilution methods; for antibiofilm activity, the crystal violet assay was used. The identification and the quantification of the different constituents of extracts were determined by reverse-phase high-performance liquid chromatography (RP-HPLC). Bacterial growth was found in three patients (5.1%). Enterococcus faecalis (1.7%), Acinetobacter baumanii (1.7%), and Pseudomonas putida (1.7%) strains were more commonly detected. They were resistant to several common antibiotics. All extracts presented several components, mainly nepetin-7-glucoside and trans-ferulic-acid, and they had antibacterial activity (MIC = 6.25 mg/mL and MBC = 6.25 mg/mL), and antibiofilm (59.70% at 25 mg/mL) properties, especially against Acinetobacter baumanii. The results achieved confirm the important role of this plant as a source of therapeutic activities.

IL-10R1 S138G loss-of-function polymorphism is associated with extrapulmonary tuberculosis risk development in Tunisia.

There is considerable evidence that host genetic factors are important in determining susceptibility to mycobacterial infections. More recently, functional genetic mutations affecting IL-10 receptor 1 (IL-10R1) were described. In this study, we investigated the relationship of IL-10R1 S138G loss-of-function polymorphism (A536G: rs3135932) with susceptibility to active tuberculosis (TB) in Tunisian patients. A total of 168 patients with pulmonary TB, 55 with extrapulmonary TB, and 150 control subjects were studied. Genomic DNA samples were extracted from leukocytes and used to investigate S138G polymorphism in IL-10R1 gene by multiplex allele-specific polymerase chain reaction. Associations between G allele [odds ratio OR=5.01; 95% confidence intervals CI=2.58-9.77; P=10(-7)], GG genotypes [OR=9.06; 95% CI (1.58-67.33); correcting P-values using the Bonferroni method for multiple tests Pc=0.015] and AG genotype [OR=3.75; 95% CI (1.62-8.7); Pc=0.0012] with the risk development of active extrapulmonary TB were found. In contrast, the AA genotype was found to be associated with resistance to extrapulmonary TB [OR=0.19; 95% CI (0.09-0.42); Pc=6.10(-6)]. No association was found between S138G SNP and pulmonary TB. In conclusion, our study suggested the possible role of IL-10R1 S138G loss-of-function polymorphism in extrapulmonary TB susceptibility-resistance in Tunisia.

Investigation of a cluster of Candida albicans invasive Candidiasis in a neonatal intensive care unit by pulsed-field gel electrophoresis.

Nosocomial invasive candidiasis (IC) has emerged as a major problem in neonatal intensive care units (NICUs). We investigated herein the temporal clustering of six cases of neonatal IC due to Candida albicans in an NICU. Eighteen isolates obtained from the six neonates and two isolates from two health care workers (HCWs) working at the same unit and suffering from fingers' onychomycosis were genotyped by electrophoretic karyotyping (EK) and restriction endonuclease analysis of genomic DNA by using Sfi I (PFGE-Sfi I). PFGE-Sfi I was more effective in discriminating between temporally related isolates. It showed that (i) both HCWs had specific strains excluding them as a source of infections in neonates. (ii) Isolates collected from three neonates were identical providing evidence of their clonal origin and the occurrence of a horizontal transmission of C. albicans in the unit. (iii) The three remaining neonates had specific strains confirming that the IC cases were coincidental. (iv) Microevolution occurred in one catheter-related candidemia case. Our results illustrate the relevance of the molecular approach to investigate suspected outbreaks in hospital surveys and the effectiveness of PFGE-Sfi I for typing of epidemiologically related C. albicans isolates.

[Epidemiological profile and antibiotic resistance of Pseudomonas aeruginosa isolates in burn and traumatology center in Tunisia over a three-year period]. / Profil épidémiologique et résistance aux antibiotiques des Souches de Pseudomonas aeruginosa isolées au centre de Traumatologie et Grands Brûlés en Tunisie durant trois ans.

BACKGROUND: Pseudomonas aeruginosa is a known opportunistic pathogen frequently causing serious infections in burned patients. AIM: To analyze the epidemiological profile of Pseudomonas aeruginosa isolated in a Tunisian burn unit. METHODS: During a 3-year period (from 01 July 2008 to 30 June 2011), 544 non repetitive strains of P. aeruginosa were isolated from burn patients. Susceptibility to antibiotics was assessed according to CA-SFM guidelines. Serotypes were identified by slide agglutination test using P.aeruginosa O antisera (Biorad). Producing carbapenemase was analyzed for 202 imipenem resistant isolates by EDTA test. Susceptibility testing data were stored in a laboratory data base using whonet 5.3 software. RESULTS: The most frequent sites of isolation were cutaneous infections and blood cultures (83.4%). The percentages of resistant isolates were as follows: ceftazidime: 34%; imipenem: 37.1%, ciprofloxacin: 27.1% and amikacin: 29.6%. The most prevalent serotypes were: 011(51%), 06(17%), 03 (8%), 04(12%), 012(5%). Among the 202 imipenem resistant strains, 58% expressed a metallocarbapenemase. All theses strains were resistant to all tested antibiotics except colistin and belonged to the serotype O11. CONCLUSION: The dissemination of carbapenemases strains must be contained by implementation of timely identification, strict isolation methods and better hygienic procedures.

Epidemiological profile and antibiotic resistance of Pseudomonas aeruginosa isolates in burn and Traumatology center in Tunisia over a three-year period.

BACKGROUND: Pseudomonas aeruginosa is a known opportunistic pathogen frequently causing serious infections in burned patients. AIM: To analyze the epidemiological profile of Pseudomonas aeruginosa isolated in a Tunisian burn unit. METHODS: During a 3-year period (from 01 July 2008 to 30 June 2011), 544 non repetitive strains of P. aeruginosa were isolated from burn patients. Susceptibility to antibiotics was assessed according to CA-SFM guidelines. Serotypes were identified by slide agglutination test using P.aeruginosa O antisera (Biorad). Producing carbapenemase was analyzed for 202 imipenem resistant isolates by EDTAtest. Susceptibility testing data were stored in a laboratory data base using whonet 5.3 software. RESULTS: The most frequent sites of isolation were cutaneous infections and blood cultures (83.4%). The percentages of resistant isolates were as follows: ceftazidime: 34%; imipenem: 37.1%, ciprofloxacin: 27.1% and amikacin: 29.6%. The most prevalent serotypes were: 011(51%), 06(17%), 03 (8%), 04(12%), 012(5%). Among the 202 imipenem resistant strains, 58% expressed a metallocarbapenemase. All theses strains were resistant to all tested antibiotics except colistin and belonged to the serotype O11. CONCLUSION: The dissemination of carbapenemases strains must be contained by implementation of timely identification, strict isolation methods and better hygienic procedures.

MCP-1 -2518 A/G functional polymorphism is associated with increased susceptibility to active pulmonary tuberculosis in Tunisian patients.

Monocyte chemoattractant protein-1 (MCP-1) plays crucial role in protective immunity against Mycobacterium tuberculosis (MT). In this study, we examined whether single nucleotide polymorphism (SNP) -2518 A/G (rs 1024611) of MCP-1 affect the susceptibility to active tuberculosis (TB) in Tunisian populations. Genomic DNA from patients with active TB (168 cases of pulmonary TB and 55 cases of extrapulmonary TB) and ethnically controls (150 cases) was genotyped for the MCP-1 -2518 A/G SNP by polymerase chain reaction fragment length polymorphism (PCR-RFLP). We observed that -2518 G allele and GG genotype (high MCP-1 producer) frequencies were significantly more elevated in active pulmonary TB group in comparison to control group [34 vs. 22%; P = 0.0007; 15 vs. 5%, P corrected for the number of genotypes (Pc) = 0.015; respectively]. Additionally, they were associated with increased risk development of this clinical form of TB [odds ratio (OR) = 1.83, 95% confidence intervals (CI) = 1.26-2.66; OR = 3.1, 95% CI = 1.28-7.76; respectively]. However, wild type allele -2518 A and AA genotype were over-represented in control group (78 and 62%) and seem to be protective factors against TB. Moreover, -2518 AA genotype was more frequent in control group and was associated with resistance against development of active pulmonary TB (OR = 0.56, 95% CI = 0.35-0.89, Pc = 0.03). Our findings confirm the key role of -2518 A/G SNP of MCP-1 and support its association with resistance/susceptibility to the development of active pulmonary TB in the Tunisian population.

Cytomegalovirus Glycoprotein Polymorphisms and Increasing Viral Load in Non-Transplant Patients with Hematological Malignancies Undergoing Chemotherapy: A Prospective Observational Study.

INTRODUCTION: Cytomegalovirus (CMV) predisposes to several clinical complications and is a major cause of morbidity and mortality in immunocompromised patients, including patients with hematological malignancies (HM). The present study was carried out to determine the distribution of CMV glycoprotein B, N, and O (gB, gN, and gO) genotypes and their potential effect on its viral load and on clinical outcomes in a cohort of Tunisian non-hematopoietic stem cell transplant (HSCT) patients with HM undergoing chemotherapy. METHODS: CMV viral load was evaluated by real-time quantitative PCR. The gB, gN, and gO genotypes of the CMV strains were analyzed by multiplex nested PCR and sequencing. RESULTS: This prospective study involved 60 clinical isolates obtained from 60 non-HSCT patients with HM undergoing chemotherapy. Mixed CMV gB, gN, and gO genotypes were the predominant glycoprotein genotypes in 31%, 41.4%, and 46.4% of patients, respectively. Mixed gB genotypes were associated with higher initial levels of CMV load (p = 0.001), increased rate of fever (0.025), and co-infection with other herpesviruses (HHVs) (p = 0.024) more frequently than in single gB genotype. Mixed gN genotypes were more associated with severe lymphopenia (ALC < 500/µL) (p = 0.01) and increased risk of death (p = 0.042) than single gN genotype. Single gO2b genotype had also a more unfavorable outcome (p = 0.009) than the other single gO genotype. Mixed gO genotypes were associated with female gender (p = 0.015), acute leukemia disease (p = 0.036), initial high level of CMV viral load (at least 1000 copies/mL) (p = 0.029), skin rash (p = 0.01) more frequently than in single gO genotype. The gO1a/gN3b linkage was associated with an increased initial viral load (p = 0.012). CONCLUSION: Infection with mixed CMV genotypes was common and multiple gB, gN, and gO genotypes were associated with clinical manifestation and higher viral load.