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.

Chemical composition of 8 eucalyptus species' essential oils and the evaluation of their antibacterial, antifungal and antiviral activities.

BACKGROUND: In 1957, Tunisia introduced 117 species of Eucalyptus; they have been used as fire wood, for the production of mine wood and to fight erosion. Actually, Eucalyptus essential oil is traditionally used to treat respiratory tract disorders such as pharyngitis, bronchitis, and sinusitis. A few investigations were reported on the biological activities of Eucalyptus oils worldwide. In Tunisia, our previous works conducted in 2010 and 2011 had been the first reports to study the antibacterial activities against reference strains. At that time it was not possible to evaluate their antimicrobial activities against clinical bacterial strains and other pathogens such as virus and fungi. METHODS: The essential oils of eight Eucalyptus species harvested from the Jbel Abderrahman, Korbous (North East Tunisia) and Souinet arboreta (North of Tunisia) were evaluated for their antimicrobial activities by disc diffusion and microbroth dilution methods against seven bacterial isolates: Haemophilus influenzae, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus agalactiae, Streptococcus pneumoniae and Streptococcus pyogenes. In addition, the bactericidal, fungicidal and the antiviral activities of the tested oils were carried out. RESULTS: Twenty five components were identified by GC/FID and GC/MS. These components were used to correlate with the biological activities of the tested oils. The chemical principal component analysis identified three groups, each of them constituted a chemotype. According to the values of zone diameter and percentage of the inhibition (zdi, % I, respectively), four groups and subgroups of bacterial strains and three groups of fungal strains were characterized by their sensitivity levels to Eucalyptus oils. The cytotoxic effect and the antiviral activity varied significantly within Eucalyptus species oils. CONCLUSIONS: E. odorata showed the strongest activity against S. aureus, H. influenzae, S. agalactiae, S. pyogenes, S. pneumoniae and against all the tested fungal strains. In addition, E. odorata oil showed the most cytotoxic effect. However, the best antiviral activity appeared with E. bicostata. Virus pretreatment with E. bicostata essential oil showed better antiviral activity (IC(50) = 0.7 mg/ml, SI = 22.8) than cell-pretreatment (IC(50) = 4.8 mg/ml, SI = 3.33). The essential oil of E. astringens showed antiviral activity only when incubated with virus prior to cell infection. This activity was dose-dependent and the antiviral activity diminished with the decreasing essential oil concentration.

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.

Investigation of the clonal dissemination of Klebsiella pneumoniae isolates producing extended-spectrum beta-lactamases in a neonatal ward, Sousse, Tunisia.

This study was designed to investigate the spread of extended-spectrum beta-lactamase producing Klebsiella pneumoniae (ESBL-Kp) strains in Sousse hospital, during 7-month period by using phenotypic and genotypic markers. A total of 57 clinical isolates of ESBL-Kp, 22 strains recovered from seriously infected neonates and 35 strains recovered from colonized neonates and hospitalized in the neonatal ward of Sousse hospital, Tunisia, was subjected to 99 carbon source utilization tests, ribotyping and pulse-field gel electrophoresis (PFGE) profiles of total genomic DNA. Biotyping, ribotyping and PFGE typing showed that four different clones circulated in the neonatal ward between January and July 1997 and suggested that the epidemic strain belonged to the same biotype, ribotype and PFGE pattern, and was represented by 18 isolates from infected neonates and 28 isolates from colonized neonates. Biotyping, ribotyping and PFGE typing appeared to be reliable methods for distinguishing K. pneumoniae strains. Biotyping, which has the advantage of simplicity and rapidity, may be used as a first screening method.

Nosocomial outbreak caused by Salmonella enterica serotype Livingstone producing CTX-M-27 extended-spectrum beta-lactamase in a neonatal unit in Sousse, Tunisia.

In this study, we report an outbreak of Salmonella enterica serotype Livingstone resistant to extended-spectrum cephalosporins that occurred in a neonatal ward of the maternity department of Farhat Hached Hospital, Sousse, Tunisia, in 2002. A total of 16 isolates were recovered from 16 babies hospitalized in the ward during the period 1 to 16 July. All these babies developed diarrhea, and three of them developed septicemia. All the isolates demonstrated resistance to ceftriaxone and ceftazidime due to the production of an extended-spectrum beta-lactamase (ESBL). The isolates were also resistant to aminoglycosides (kanamycin, tobramycin, netilmicin, gentamicin, and amikacin) and sulfamethoxazole-trimethoprim. DNA profiles were determined by pulsed-field gel electrophoresis using the XbaI and SpeI endonucleases and by ribotyping with PstI digestion. They yielded the same patterns, showing that the outbreak was caused by a single clone. The ESBL was identified as CTX-M-27 by sequencing of PCR products and by isoelectric focusing. The ESBL resistance was transferred by a 40-kb conjugative plasmid. The mobile insertion sequence ISEcp1 was found to be located upstream of bla(CTX-M-27) in the same position as that known for a bla(CTX-M-14) sequence. A new gene named dfrA21, encoding resistance to trimethoprim and carried by a 90-kb plasmid, was characterized. The dfrA21 gene was inserted as a single resistance cassette in a class I integron. The babies were treated with colistin, and all except two recovered. The outbreak came to an end when appropriate actions were taken: patient isolation, hand washing, and disinfection of the ward.