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.

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.

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.

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.

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.

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.

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.

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.

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.

Serotype distribution and antimicrobial resistance of invasive and noninvasive pneumococcal isolates in Tunisia.

Pneumococcal conjugate vaccines have not yet been introduced into the national program for childhood vaccination in Tunisia. The aim of this 7-year study was to obtain local data about serotype distribution and antimicrobial resistance of Streptococcus pneumoniae. A total of 203 isolates of culture confirmed that S. pneumoniae was evaluated. Invasive (n=108) and noninvasive (n=95) pneumococcal isolates were obtained from patients aged from 1 month to 85 years old. Considering all age groups, vaccine coverage was 40%, 62%, and 68% for PCV7, PCV10, and PCV13 serotypes, respectively. Overall, 31% of these isolates were penicillin G nonsusceptible. The most prevalent serotypes identified were those found in currently available pneumococcal conjugate vaccines, emphasizing the importance of implementing the vaccine in the routine immunization schedule at the national level.

Comparison of LED and conventional fluorescence microscopy for detection of acid-fast bacilli in an area with high tuberculosis incidence.

The objective of the study is to compare the performance of conventional fluorescence microscopy (CFM) and light-emitting diode (LED) fluorescence microscopy (FM) for detection of acid-fast bacilli (AFB) in clinical samples. We included AFB smears, stained using the auramine O method and blindly examined with both CFM and LED-FM. Culture results were used as reference for evaluating the reliability of the FM. We included 180 culture positive specimens and an equal number of culture negative specimens. Sensitivities for the CFM and LED-FM were 79.4% and 82.2%, respectively. Both microscopes had a high specificity (97.2%). The negative-positive (>1 cross) inter-reader agreement of LED-FM and CFM was excellent. Therefore, detection of scanty AFB was higher with LED-FM. Both microscopes were equivalent with respect to time required to read smears. Although it was not faster than CFM, the higher detection of scanty AFB smears combined with ease of use supports the consideration of LED microscopy by all tuberculosis diagnostic laboratories, as a replacement for conventional fluorescence microscopes.

[Evaluation of chromogenic medium Uriselect4 in urine culture]. / Évaluation du milieu chromogène Uriselect4 au cours des urocultures.

We evaluated the performance and the cost of chromogenic medium Uriselect4 agar with regard to the standard medium for the detection and identification of urinary tract pathogens. A total of 503 clinical urine specimens containing leucocytes greater or equal to 104/mL were analysed prospectively, in parallel by two different persons on blood agar (GS) and Uriselect4 according to the manufacturers' instructions. Of the 503 urine specimens tested, 210 gave a positive culture on Uriselect4 versus 181 on GS. The majority of bacterial species grew on both media; enterobacteria grew on Uriselect4 better than GS. The identification of Escherichia coli (E. coli), Proteus mirabilis (P. mirabilis), KES group and Enterococcus faecalis (E. faecalis) did not require the use of galleries Api and has a gain of 24  h. Positive pure cultures on Uriselect4 corresponding to negative cultures of GS were noted in 17 ases. Conversely, in seven cases a positive pure culture on GS was noted while the corresponding Uriselect4 cultures were negative. The cost of identification on GS (including the cost of galleries Api), was about two times higher than Uriselect4. Uriselect4 medium isolates the most frequent urinary tract pathogens and identify them so almost immediately, with a lower cost.

Evaluation of an immunochromatographic assay for rapid identification of Mycobacterium tuberculosis complex in clinical isolates.

Identification of Mycobacterium tuberculosis complex (MTC) remains slow. Over the years, several new technologies have been proposed to accelerate and simplify the detection of MTC. In this context, we evaluated an immunochromatographic assay (ICA) (BIO-LINE SD Ag MPT64 TB) for rapid identification of MTC, based on detection of a specific MPT64 antigen of MTC. We have tested it on i) mycobacterial cultures: 210 MTC strains and 28 nontuberculous mycobacteria; ii) M. bovis bacille Calmette-Guérin strain SSI (Statens Serum Institut, Denmark); and iii) 22 microorganisms other than mycobacteria, isolated from cultures. We concluded that this kit has an excellent specificity (100%) and sensitivity (99%) from isolated cultures. The ICA (BIO-LINE SD Ag MPT64 TB) allows excellent MTC identification from clinical isolates. It is a rapid, simple, and inexpensive test, and has a definite contribution in the rapid laboratory diagnosis of tuberculosis.

Evaluation of the diagnostic value of measuring IgG, IgM, and IgA antibodies to mycobacterial A60 antigen in active tuberculosis.

The purpose of the present study was to evaluate the clinical usefulness of detection of serum immunoglobulin A (IgA), IgG, and IgM antibodies raised against the mycobacterial A60 antigen for the diagnosis and discrimination of active tuberculosis (TB) from other pulmonary diseases. Three commercially available ELISA kits (IgA, IgG, and IgM) (ANDA Biologicals, Strasbourg, France) were evaluated simultaneously in 246 serum samples from 3 groups of patients: group I, 171 patients with active TB (128 pulmonary TB and 43 extrapulmonary TB); group II, 73 patients with pulmonary non-TB diseases; and group III, 2 leprosies patients. The sensitivities of tests ranged from 31.3% (IgA) to 94% (IgG) in pulmonary TB patients and from 21% (IgA) to 84% (IgG) in extrapulmonary TB patients. The specificities of assays varied from 92% (IgG) to 96% (IgA) in the pulmonary non-TB group. Combination of IgG with IgA and/or IgM does not improve its sensitivity. Clinical use of the A60-based serodiagnostic IgG assay is of great value for the rapid diagnosis and discrimination between active TB and pulmonary non-TB diseases. Moreover, this test could be used to increase diagnostic accuracy, especially for smear-negative TB cases, which are difficult to diagnose.

Rapid detection of Mycobacterium tuberculosis in sputum by Patho-TB kit in comparison with direct microscopy and culture.

The usefulness of a new rapid diagnostic test (Patho-TB) using antibodies specific to mycobacterial antigens was evaluated for the rapid discrimination between pulmonary tuberculosis (TB) and non-TB pulmonary diseases on sputa. One hundred sputa collected from 79 active TB patients and from 21 patients with non-TB pulmonary diseases (asthma and chronic obstructive pulmonary disease) were enrolled into the study and tested for the presence of Mycobacterium tuberculosis by Ziehl-Neelsen smear, Patho-TB kit, and Löwenstein-Jensen culture. The sensitivity, specificity, positive predictive value, and negative predictive value of the Patho-TB test were 95%, 100%, 100%, and 84%, respectively. Patho-TB test is simple, quick, and easy to perform. Its sensitivity, specificity, and positive predictive value are satisfactory. Therefore, it could be used as a screening test in poorly equipped laboratories of TB endemic areas.

[Clinical, epidemiologic and bacteriological characteristics of urinary tract infections due to Staphylococcus saprophyticus in the central part of Tunisia]. / Caractéristiques cliniques, épidémiologiques et bactériologiques des infections urinaires à Staphylococcus saprophyticus dans le centre de la Tunisie.

AIM: We assess the clinical, epidemiologic and bacteriological aspects of urinary tract infections due to S. saprophyticus through a sample collected in the central part of Tunisia. METHODS: Retrospective study, related to 92 strains of S. saprophyticus, isolated among positive urinary specimens in 2006. Considered data were: sex, age, original departments, symptoms, type of urinary tract infection, diagnosis date and susceptibility of strains to antibiotics. RESULTS: Patients are young women in 98% (average age: 31.5 years) with cystitis in 99%. They are outpatients in 90%. S. saprophyticus represents 2.8% of all uropathogens; it is the first cocci with positive Gram (28.2%). Any seasonal variation is noticed. S. saprophyticus has shown higher susceptibility to antibiotics than other staphylococci; cotrimoxazole, fluoroquinolons and nitrofurans represent the best treatment. CONCLUSION: S. saprophyticus is responsible of cystitis in young women. There is no seasonal variation in our area. This community staphylococci is very susceptible to antibiotics.