[Panton-Valentine leukocidin-positive osteoarticular infections]. / Infections ostéoarticulaires à Staphylococcus aureus portant le gène de la leucocidine de Panton-Valentine.

OBJECTIVES: The aim of our study was to evaluate the frequency of osteoarticular infections with Panton-Valentine leukocidin-positive (PVL) Staphylococcus aureus (PVL-SA) among patients admitted to the orthopedic ward at the Sahloul University Hospital (Sousse, Tunisia) and to study the characteristics of these strains and patients. MATERIALS AND METHODS: We conducted a retrospective descriptive study over a 5-year period. Bacterial identification, antibiotic susceptibility, and molecular study (PCR to detect of the luk-PV gene that encodes PVL) were performed for 44 S. aureus isolates. RESULTS: Panton-Valentine toxin was found in 41% of S. aureus cases, mainly males, and 39% of the PVL(+) cases were methicillin-sensitive (MSSA). These strains constitute a reservoir of PVL genes that can lead to the emergence and spread of PVL-SA clones resistant to methicillin (MRSA). In our series, PVL-MRSA accounted for 9% of all S. aureus isolates. Their profile and antibiotic resistance is that of clone ST80, frequently isolated in Europe and also reported in Algeria and Tunisia. CONCLUSION: It is desirable to test for PVL routinely in the laboratory to implement appropriate treatment and to monitor the epidemiology of these PVL-SA strains actively. Further measures should be undertaken to prevent and fight infections by these strains.

Relationship between electropherotypes and VP7/VP4 genotypes of group A rotaviruses detected between 2000 and 2007 in Tunisian children.

BACKGROUND: Rotaviruses are the most frequent agents associated with diarrhoea in children worldwide. Analysis of mobility of the 11 segments of genomic RNA by polyacrylamide gel electrophoresis (PAGE) yields a pattern which is characteristic for a particular rotavirus isolate. The group A rotaviruses can be further characterized by analysis of VP7 and VP4 genes specificities, responsible for rotavirus classification into G and P genotypes, respectively. The aim of the present study was to detect a relationship between electropherotype pattern and molecular characteristics of the rotavirus strains. MATERIAL AND METHODS: Were analyzed 278 rotavirus-positive specimens by PAGE and G/P-genotyped by multiplex semi-nested RT-PCR. Pearson's correlation tests were used for statistical analysis. RESULTS: Twelve different electropherotypes were visualized, eight with a long profile (186 cases) and four with a short one (87 cases). Concerning VP7 types, G2 viral strains were found to be predominant and were detected in 91 specimens (32.7%). Strains with G1, G3, G4, G8 and G9 specificities were detected in 62 (22.3%), 82 (29.5%), 13 (4.7%), two (0.7%) and seven cases (2.5%), respectively. The results of VP4 genotyping showed a predominance of P[8] genotype which comprised half of the strains identified (139 cases, 50%). VP4 P[4], P[6] and P[11] were found in 83 (29.9%), 31 (11.1%) and 11 (4.0%) specimens, respectively. A high rate of mixed strains was also found (1.8% mixed electropherotypes, 7.6% G-mixed and 5% P-mixed strains). Electropherotype pattern of rotavirus strains was significantly correlated with VP7 genotype (p=0.018) and with VP4 genotype specificities (p<0.001).

[Evolution of group A Rotavirus strains circulating in Tunisia over a 3-year period (2005-2007)]. / Évolution des souches de Rotavirus du groupe A en circulation en Tunisie sur une période de trois ans (2005-2007).

BACKGROUND: Rotaviruses are the most frequent agents associated with diarrhoea in children worldwide. Analysis of mobility of the 11 segments of genomic RNA by polyacrylamide gel electrophoresis (PAGE) yields a pattern which is characteristic for a particular rotavirus isolate. The group A rotaviruses can be further characterized by analysis of VP7 and VP4 genes specificities, responsible for rotavirus classification into G and P genotypes, respectively. The aim of the present study was to determine the evolution of group A Rotavirus strains circulating in Tunisia over a 3-year period (2005-2007). MATERIAL AND METHODS: A total of 1503 stool samples collected from children less than five years old, consulting or hospitalised in Tunisia for diarrhoea between 2005 and 2007, were screened for the presence of group A Rotaviruses. Rotavirus-positive specimens were further analyzed by PAGE and G/P-genotyped by multiplex semi-nested RT-PCR. RESULTS: Rotaviruses were detected in 323 stool samples over 1503 (21 %). Long electropherotypes predominated in Tunisia during the whole period of study (N=158 vs N=82 short electropherotypes). VP7 genotyping showed the cocirculation of five different genotypes: G1, G2, G3, G4 and G9. VP4 typing detected four different P-genotypes: P[8], P[4], P[6] and P[11]. Rotavirus strains with G3P[8] specificity were predominating in Tunisia in 2005 and 2006, replaced by G2P[4] strains in 2007.

Clinical Features of Rotavirus Infections : Influence of Child Age on Clinical Manifestations

Objectifs : Decrire les caracteristiques cliniques des infections a Rotavirus et comparer les symptomes observes en fonction de l'age des enfants. Malades et methodes : Les dossiers cliniques de 278 enfants de moins de 5 ans infectes par le Rotavirus ont ete consultes retrospectivement. La presence d'antigenes de Rotavirus du groupe A dans les selles a ete detectee par la technique immunoenzymatique. Une correlation statistique entre les signes cliniques et l'age des enfants a ete recherchee au moyen des tests de correlation de Pearson. Resultats : Parmi les 278 enfants positifs a Rotavirus; 93;9ont presente une diarrhee; 79;1des vomissements; 71;6de la fievre; 37;4des signes respiratoires et 33;1des troubles neurologiques. Une rehydratation intraveineuse requise pour 59;7des enfants. D'une facon generale; la diarrhee (p = 0;001); les vomissements (p = 0;007); la fievre (p=0;045); les troubles respiratoires (p = 0;01) et la deshydratation (p 0;001) etaient significativement plus frequents chez les nourrissons de 1-24 mois par rapport aux autres enfants infectes. Conclusion : La severite du syndrome clinique induit par les infections a Rotavirus semble etre directement influencee par l'age de l'enfant. Il etait interessant de noter que les nourrissons de 1 a 5 mois ont presente des formes cliniques souvent aussi severes que ceux de 6 a 24 mois

[Tumoral form of abdominal actinomycosis: a retrospective case series of seven patients]. / Actinomycoses abdominales à forme tumorale : une série rétrospective de sept observations.

PURPOSE: Abdominal actinomycosis is an uncommon chronic infectious disease due to Actinomyces, a Gram-positive bacteria. This saprophytic bacteria of digestive tract and genital mucosa can occasionally become pathogenic mimicking a digestive neoplasia. The aim of this study was to underline diagnostic features of abdominal actinomycosis and to summarize data about clinical, diagnostic and therapeutic approach of this type of infection. PATIENTS: From January 1995 to December 2007, retrospective data concerning patients with abdominal actinomycosis who were followed-up in the University Hospital Sahloul (Sousse, Tunisia) were analysed. RESULTS: Seven patients with abdominal actinomycosis were identified during the study period. All presented with an abdominal mass. The diagnosis of actinomycosis was obtained after surgical resection in all cases. The histological study permitted the diagnosis in six cases, and the surgical samples grew up Actinomyces in two patients. For the five patients who received prolonged and adapted antibiotic therapy, a favourable outcome was observed. CONCLUSION: Actinomycosis must be included in the differential diagnosis of invasive abdominal lesions with "malignant appearance".

Salmonella non typhoidique : une cause rare d'infection urinaire

Le but de notre travail est d'analyser les aspects cliniques; bacteriologiques et therapeutiques des infections urinaires a Salmonella non typhi (SNT) dans notre region. Patients et methodes : Il s'agit d'une etude descriptive retrospective ayant concerne les cas d'infections urinaires a SNT diagnostiques a l'hopital Sahloul (Sousse; Tunisie) recenses sur une periode de six ans et demi (Janvier 2003-Juin 2009). Les souches ont ete identifiees grace a leurs caracteres morphologiques; biochimiques et antigeniques. Un antibiogramme a ete effectue. Resultats : 9 cas d'infection urinaire a SNT ont ete ainsi recenses; soit 0;079des infections urinaires colligees au laboratoire de microbiologie durant la meme periode. L'age moyen des patients etait de 45 ans. Un terrain debilite etait note chez 8 des 9 patients. Les facteurs favorisants notes etaient variables et parfois associes chez un meme patient: diabete (4 cas); traitement corticoide et immunosuppresseur (3 cas); insuffisance renale (3 cas); reflux vesico-uretral (1 cas); pathologie tumorale (4 cas); lupus erythemateux systemique (1 cas); hypertrophie prostatique (1 cas). Les serotypes notes etaient Salmonella enteritidis (8 cas); Salmonella typhimurium (1 cas). L'evolution sous antibiotherapie adaptee (duree moyenne de 16.4 jours) etait favorable dans 7 cas. Conclusion : L'infection urinaire a SNT survient en regle sur un terrain predispose notamment un diabete sucre; une uropathie ou un etat d'immunodepression. Le traitement antibiotique doit etre suffisamment prolonge pour eviter les complications et les recidives

[Characterization of the resistance mechanism to beta-lactams in Acinetobacter baumannii strains isolated in the university hospital Sahloul in Tunisia (2005)]. / Caractérisation des mécanismes enzymatiques de résistance aux beta-lactamines chez des souches de Acinetobacter baumannii isolées à l'hôpital universitaire Sahloul, Sousse en Tunisie (2005).

OBJECTIVE: The bacterial multiresistance to beta-lactams and imipenem is an emergent feature in the university hospital Sahloul in Tunisia. This study was conducted to elucidate natural and acquired mechanism of resistance to beta-lactams in strains of Acinetobacter baumannii isolated in different wards of the hospital. MATERIALS AND METHODS: A specimen of 26 clinical strains of Acinetobacter baumannii was studied. beta-lactamases characterization was done by isoelectric focusing on gel of crude enzymatic extract, phenotypic tests for detection of extended spectrum beta-lactamases (ESBL) and metallo-beta-lactamases (MBL) and finally by amplification (PCR) and sequencing of genes encoding naturally occurring AmpC, the insertion sequence ISAbaI and oxacillinase with carbapenemase activity. Study of clonality of strains was performed by analysis of genomic DNA digested by the restriction enzyme ApaI and separated by pulsed field gel electrophoresis (PFGE). RESULTS: The isoelectric focusing on gel revealed two bands of beta-lactamase activity with a pI upper than 8. None ESBL or MBL was detected. PCR for AmpC, ISAbaI and OXA-69 were positive for all studied strains. The sequencing of PCR products show high identity (99-100%) with genes described previously. PFGE analysis has demonstrated clonality of studied strains. CONCLUSION: Resistance to beta-lactams including imipenem is associated to the hyper production of the AmpC enzyme and expression of OXA-69. Those enzymatic mechanisms are associated with the natural low permeability to beta-lactams which characterize Acinetobacter baumannii strains. High clonal relationship of studied strains proved by PFGE analysis has shown the necessity of implementation of strict hygienic rules and rational antibiotic usage.

Molecular diversity of the aminoterminal region of the G protein gene of human respiratory syncytial virus subgroup B.

Two major antigenic subgroups (designated A and B) have been described for human respiratory syncytial virus (HRSV). Between and within the two main subgroups, there is antigenic variation in the attachment protein G. The variability of the G protein is known to be located in two hypervariable regions of the ectodomain. Most investigators have studied the gene segment coding the C-terminal end of the protein, and little is known about the N-terminal variable region. In the present study, the genetic variability of HRSV subgroup B was evaluated by nucleotide sequencing of the N-terminal region of the G gene of 52 Tunisian isolates. Tunisian subgroup B isolates clustered into two main lineages designated arbitrarily as Tu-GB1 and Tu-GB2. Three distinct subtypes were identified within genotype Tu-GB2. The inter- and intragenotype nucleotide variability ranged from 4 to 8% and from 0 to 4%, respectively. Overall divergence values of the G sequences were inferior or equal to 15% at the aminoacid level. Comparison of sequences among Tunisian HRSV strains and viruses isolated in other geographical areas during different epidemics demonstrated close similarity to strains from Kenya, Belgium, the UK, Qatar, Canada and South Korea.

[Clinical and epidemiological characterization of infections due to imipenem resistant Acinetobacter baumannii at the university hospital Sahloul, Tunisia]. / Caractérisation clinico-épidémiologique des infections à Acinetobacter baumannii résistant à l'imipénème au CHU Sahloul, Tunisie.

OBJECTIVE: to characterize epidemiological and clinical features related to the multi-drug Acinetobacter baumannii infections in the university hospital Sahloul in Tunisia. MATERIAL AND METHODS: retrospective study including twenty-four imipenem resistant Acinetobacter baumannii isolated from twenty patients hospitalized in different wards of the hospital. Study of clinical features related to the infection by multi-drug Acinetobacter baumannii, bacterial identification by classical identification scheme, antibiotic susceptibilities were determined by the disk diffusion method; genotyping was performed by arbitrarily-primed PCR. RESULTS: the most incriminated ward was the intensive care unit with a high prevalence of septicaemia. All studied strains were multi-drug to all beta-lactams tested. Genotyping has shown the clonality of studied strains. Features incriminated in the acquisition of infection were essentially immunodeficiency, invasive manoeuvring and antibiotherapy. CONCLUSION: multidrug Acinetobacter baumannii is increasingly isolated in our hospital. Rational use of antibiotics and rigorous application of hygienic rules could contribute to limit dissemination of such strains.

[Prevalence of adenovirus antigens in children presenting with acute diarrhoea]. / Prévalence des antigènes d'adénovirus chez les enfants atteints de diarrhée aiguië.

Viral diarrhoea remains a major cause of childhood morbidity and mortality worldwide. Four major categories of viruses are now recognized as clinically important, including rotavirus, astrovirus, adenovirus, and calicivirus. This retrospective epidemiological study was conducted in the East centre part of Tunisia. A total of 638 stool samples were collected from children under 5 years of age presenting with acute diarrhoea at hospitals the East centre part of Tunisia between October 2003 and September 2005. All samples were analyzed using commercially available immunoenzymatic assay (EIA) kits to detect specific adenovirus antigens. Samples positive for adenovirus antigen were further screened using an ELISA technique allowing specific detection of species F enteric adenovirus types 40 and 41. Adenovirus was detected in 6% of the stools tested using ELISA. Among stool samples testing positive for adenovirus, 57% (20/35) were found to contain species F adenovirus types 40/41. In addition to diarrhoea that was present in all children studied, vomiting and fever were observed in 89% and 53% respectively and were associated with respiratory troubles in 32%. Enteric adenoviruses appear to play an important role in paediatric diarrhoea in Tunisia. Use of simple effective viral diagnostic techniques in paediatric hospitals could improve patient care by reducing unnecessary use of antibiotics.

[Opsoclonus-myoclonus syndrome associated with Mycoplasma pneumoniae infection]. / Syndrome opsoclonie-myoclonie associé à une infection à Mycoplasma pneumoniae.

UNLABELLED: Mycoplasma pneumoniae infection is associated with various manifestations involving the central nervous system but it has never been reported as a potential aetiology of opsoclonus-myoclonus syndrome (OMS) in children. OBSERVATION: We report on a case in a 4-year-old girl who presented neurological manifestations compatible with an OMS, after a respiratory tract disease. Aetiological investigations revealed M. pneumoniae infection as specific IgM were present in the serum (Elisa). Evolution after corticosteroid, intravenous immunoglobulins and macrolide therapy was favourable as clinical symptoms disappeared. After a 12-month follow-up, the patient has no neurological sequela. CONCLUSION: M. pneumoniae infection should be added to the list of causes to be screened in OMS. Its pathophysiology remains unknown but may involve a dysimmune postinfectious mechanism.

Group A rotavirus strains circulating in the eastern center of Tunisia during a ten-year period (1995-2004).

An epidemiological survey investigating rotavirus infections in children was undertaken in the Eastern Center of Tunisia between January 1995 and December 2004. A total of 982 faecal specimens collected from children less than 5 years in age were screened by enzyme-linked immunosorbent assay (ELISA) or latex agglutination assay for the presence of group A rotavirus antigen. Rotavirus-positive samples were used for G and P typing by multiplex semi-nested reverse transcription-PCR. Rotaviruses were detected in 22% (n = 220) of stools. Of these, 164 were typed for VP7: G genotypes found were G1 (59%), G2 (2%), G3 (9%), G4 (10%), G8 (1%), and G9 (1%). Sixteen specimens (9%) showed mixed G profiles. A total of 119 specimens were typed for VP4. P genotypes detected were P[8] (32%), P[6] (15%), and P[4] (13%). Mixed P profiles were also detected (6%). Although the distribution of the detected genotypes appeared to change annually, G1P[8] rotavirus strains always predominated during the 10-year period of study. This is the first report of rotaviruses in Tunisia with unconventional VP7 serotypes such as G8 and G9, highlighting the need for continual surveillance of emerging strains in Northern Africa. Indeed, the new commercial vaccines only contain the VP7 genes that dictate G1 or G1 to G4 specificities. These vaccines may protect less well against unusual strains circulating in countries planning to implement a rotavirus vaccine strategy.

Identification of viral agents causing diarrhea among children in the Eastern Center of Tunisia.

Viral diarrhea remains a major cause of childhood morbidity and mortality worldwide. In Tunisia, no comprehensive studies of all viral agents related to diarrhea in children have yet been conducted. The present study was performed to investigate the role of enteric viruses in acute diarrhea in the country. Six hundred thirty-eight stool samples were collected from children under 5 years of age seeking medical care for acute diarrhea between October 2003 and September 2005 in hospitals from the Eastern-Center Tunisia. All samples were tested for rotavirus, astrovirus, and adenovirus using commercial antigen enzyme immunoassays (EIAs). Positive samples for rotavirus and astrovirus were confirmed by an "in-house" reverse transcriptase-polymerase chain reaction (RT-PCR). Samples positive for adenovirus antigen were subjected to further EIA screening for species F enteric adenovirus types 40 and 41. At least one viral agent was found in 30% of the specimens. The frequency of rotavirus, astrovirus, and adenovirus was 20%, 7%, and 6%, respectively. Of the stool samples containing adenovirus, 57% (20/35) were found to be positive for species F adenovirus types 40/41. Dual infections were found in 9% (17/191) of the positive samples. Enteric viruses appear to play an important role in pediatric diarrhea in Tunisia. The introduction of affordable viral diagnosis in pediatric hospitals will improve patient care by reducing the unnecessary use of antibiotics.

[Molecular characterization of invasive Haemophilus influenzae strains isolated in Tunisia]. / Caractérisation moléculaire des souches invasives d'Haemophilus influenzae isolées dans la région du Sahel tunisien.

We reported a molecular characterization of 25 Haemophilus influenzae strains derived from cases of meningitis and sepsis in children aged less than five years hospitalized in pediatric wards from three hospitals in the Sahel area (Tunisia) during the period 1997-2002. These strains were biotyped and subjected to a capsular typing by Slide agglutination serotyping and Polymerase Chain Reaction (PCR). The genetic polymorphism of these strains was also studied in Arbitrarily Primed Polymerase Chain Reaction (AP-PCR) with two sets of primers: RAP IV and 217 delta(2) as in Pulsed Field Gel Electrophoresis after digestion of the total DNA with the restriction enzyme SmaI (PFGE SmaI). Nineteen strains among 25 (76%) were of biotype I. The bexA gene was highlighted in 13 strains (52%) and in all the cases it was of the type b. Twelve strains (48%) were shown to be unencapsulated by PCR. AP-PCR RAP IV (23 genotypes/25 with a discrimination index ID=0.993) had shown nearly the same discriminatory power than PFGE (20 genotypes/21 strains with a discrimination index ID=0.995). We thus note, how capsular typing by PCR is more sensitive than slide agglutination serotyping. We also note the genetic diversity of the invasive strains isolated with a remarkable presence of non typable strains. AP PCR seems to be an alternative of choice for the epidemiologic follow-up of the Haemophilus influenzae invasive infections.

Comparison of three primer sets for the detection of Mycobacterium tuberculosis in clinical samples by polymerase chain reaction.

A number of studies have underlined the interest of the polymerase chain reaction (PCR) in the detection of Mycobacterium tuberculosis in clinical samples. Among the different parameters to be carefully studied the choice of target gene and primers is essential. The amplification of nucleotidic sequences localised on three different target genes (groEL, IS6110, Pab) was examined in 196 clinical samples from patients with suspected tuberculosis or receiving antituberculous therapy. The results obtained after hybridization with non-radioactive labelled probes were compared with the culture data. None of the primer sets studied showed a satisfactory sensitivity (79% to 84%) suitable for it to be used alone. The false-negative specimens with the PCR tests usually corresponded to those that contained few mycobacteria. With the methods described in this study, the use of two or three primer sets located on different target genes allowed to improve the positivity rate compared to the culture and sensitivity of the test (90-98%), particularly for paucibacillary samples. On the other hand, the interpretation was easier when concordant results were obtained.

Cell surface hydrophobicity of 88 clinical strains of Acinetobacter baumannii.

We studied the surface hydrophobicity of 88 Acinetobacter baumannii strains of clinical origin, using both salt aggregation and adherence to paraxylene tests. Strains were divided into 2 groups: the first included 65 strains isolated from various clinical samples (infected catheters, tracheal and bladder devices); the second included 23 strains isolated from skin obtained from healthy controls. High surface hydrophobicity was observed in 92% of the first group of strains and in only 5% of the second.

[Fast identification of Streptococcus pyogenes serotype M.12 in throat swabs by an improvised coagglutination technique]. / Identification rapide de Streptococcus pyogenes sérotype M. 12 dans les prélèvements de gorge par coagglutination extemporanée.

A rapid procedure for identification of Streptococcus pyogenes serotype M. 12 directly in throat swabs, is reported and compared with standard culture method on blood agar plates and typing of group A Streptococci isolated, with double gel immuno-diffusion. This procedure consist of chlorhydric acid extraction of swabs and testing of the extract towards specific M. 12 protein serum using extemporaneous coagglutination technique. We have tested 1100 throat swabs, with this procedure and with standard culture procedure. Identification of group A Streptococci serotype M. 12 with reported method is obtainable within 30 to 45 minutes of receipt of the clinical specimen. This method is easy to perform, with a sensitivity and a specificity respectively: 89.7% and 98.8%.