Human T-lymphotropic virus type 4 and the human immunodeficiency virus in West Africa.

A new human T-lymphotropic virus (HTLV-4) was recently described in healthy people from Senegal. This virus has many properties in common with members of the human T-lymphotropic viruses, particularly the human immunodeficiency virus or HIV, the etiologic agent of acquired immune deficiency syndrome (AIDS), but does not appear to be associated with immunodeficiency-related disorders. In the present study, serum samples were obtained from 4248 individuals from six West African countries, including Senegal, Guinea, Guinea Bissau, Mauritania, Burkina Faso, and Ivory Coast. These samples, collected during 1985-1987, were from people categorized as healthy control, sexually active risk, and disease populations. All samples were analyzed for reactivity to HTLV-4 and HIV by radioimmunoprecipitation-sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. Evidence for HTLV-4 infection was found in five of the six countries. The seroprevalence varied markedly from country to country. Healthy sexually active individuals in the risk category had the highest levels of HTLV-4 infection compared to individuals in the healthy control category and the disease category, the latter including AIDS patients. The seroprevalence of HIV infection in most of these countries was quite low, although tightly associated with the rare cases of AIDS. The biology of HTLV-4 infection thus differs from that of HIV in Central Africa or the United States and Europe. The presence of these viruses and their different pathogenicities in several countries of West Africa indicate the necessity for serologic assays that will distinguish between them. Further studies of their origin and distribution as well as of their biology will be important in advancing our understanding of AIDS.

[Nosocomial infections: main causative agents]. / Les infections nosocomiales: agents responsables.

INTRODUCTION: Nosocomial Infections acquired within a care unit, may be related to various agents (Bacteria, virus, fungi, parasites...). The study purpose is to give relevent data on the main causative agents. MAIN AGENTS: The authors have shown the prevalent role of bacteria, mainly Enterobacteria, Staphylococcus and Pseudomonas; Legionella is also frequently isolated in some countries. Multiresistant Bacteria could be sometimes associated to nosocomial infections and severe infections. Among Nosocomial Virus: VRS, Rotavirus, Hepatitis B and C Viruses, HIV, Influenza Virus are cited. Fungal Agents (Aspergillus, Candida), Plasmodium, Non Conventional Agents (Prions) are also causative agents of Nosocomial Infection. CONCLUSION: The Isolation of contagious Agent in a hospitalized patient is not the only criteria for Nosocomial Infection typing; Rigorous analysis needed to be done for every case.

Class 2 integron-associated antibiotic resistance in Shigella sonnei isolates in Dakar, Senegal.

Forty-three Shigella sonnei isolates from adult patients with diarrhoea in Dakar were analysed for the presence of integrons. Isolates were resistant to sulphamethoxazole, trimethoprim, tetracycline, streptomycin and spectinomycin. A high prevalence of class 2 integrons (93%) was found. These integrons showed three distinct structures: a class 2 integron, part of the Tn7 family and its derivatives, carrying four cassettes in the order dfrA1-sat-aadA1-orfX; a truncated class 2 integron, without orfX; and a third type ca. 4 kb in size. These class 2 integrons probably play a role in the spread of multiresistance in S. sonnei isolates. To our knowledge, this is the first description of class 2 integrons in S. sonnei isolated in sub-Saharan Africa.

Perinatal transmission of hepatitis B virus in Senegal, west Africa.

We studied 152 healthy pregnant women and their 156 newborns for markers of hepatitis B virus (HBV) infection in Dakar, Senegal. Of these, 120 mothers (79%) had antibodies to the hepatitis B core antigen (anti-HBc), 21 (13.8%) were hepatitis B surface antigen (HBs Ag) positive, including 2/21 (9.5%) hepatitis B core-associated antigen (HBe Ag) positive and 1/21 (4.7%) HBV DNA positive. At birth, 11 (7%) infants were HBs Ag positive; 9/11 had an HBs Ag positive mother. Ten of these HBs Ag positive-born infants were investigated at 6-7 months: 5 were strongly HBs Ag positive and developed antibodies to HBs Ag, HBc Ag or HBe Ag; these 5 (3.2% of the total) probably became chronic carriers of HBV. The 5 others were HBs Ag negative and 4/5 did not develop antibodies against HBV Ag; HBs Ag positivity at birth was likely due to contamination of the mother's blood. Thirty-one of the 145 HBs Ag negative-born infants were studied at 6-7 months and remained HBs Ag negative. However, 5 (16%) showed evidence of HBV infection occurring between 0 and 6 months, as shown by the development of antibodies to HBs Ag, HBc Ag, and/or HBe Ag. Despite the low prevalence of HBV DNA and HBe Ag in HBs Ag positive African mothers, this study shows the occurrence of perinatal transmission of HBV in West Africa, in contrast with previous studies. Perinatal HBV transmission could explain the HBV vaccination failure recently reported in children in Senegal.

Phenotypic and genotypic characterization of Vibrio cholerae isolates from a recent cholera outbreak in Senegal: comparison with isolates from Guinea-Bissau.

A total of 127 strains of Vibrio cholerae (117 V. cholerae O1 and 10 nonagglutinating strains) isolated from a recent cholera outbreak in Senegal and four strains isolated in Guinea-Bissau (during the survey of a cholera epidemic that occurred 10 months before the Senegalese one) were analyzed. Strains were characterized by conventional methods (biochemical and serologic identification, susceptibility to antimicrobial agents), polymerase chain reaction for genes encoding cholera toxin (CtxA), zonula occludens toxin (Zot), and accessory cholera enterotoxin (Ace), and by ribotyping. Conventional methods showed that all strains of V. cholerae O1 belonged to serotype Ogawa, biotype El Tor and were resistant to the vibriostatic agent O129 (2,4-diamino 6,7-diisopropylpteridine phosphate), cotrimoxazole, and chloramphenicol; all strains were sensitive to tetracycline, a drug that has been extensively used in cholera therapy. Most of these V. cholerae O1 (112 strains from Senegal and four strains from Guinea-Bissau) had an intact core region (virulence cassette) and amplified a 564-basepair (bp) fragment of ctxA, a 1083-bp fragment of zot, and a 314-bp fragment of ace. Ribotyping of V. cholerae O1 strains after Bgl I restriction of total DNA revealed that ribotype B5a, which is the predominant ribotype of this seventh pandemic of cholera, was not isolated. Instead, a new ribotype was identified and designated B27 in our data bank. Since O1 isolates from Guinea-Bissau and Senegal have the same biotype, serotype, and ribotype and as the Guinea-Bissau outbreak that preceded the one in Senegal, this emerging ribotype probably came from Guinea-Bissau. Nonagglutinating strains exhibited no resistance to the O129 agent and to the tested antibiotics, they were all negative for virulence cassette, except for one strain with the ctxA and zot genes isolated from a patient with diarrhea, and there was a great variability of ribotypes among these strains. There was no difference between environmental O1 strains isolated from water and strains isolated from patients with cholera, suggesting that fecally contaminated water is an important reservoir for infection.

Rapid susceptibility testing of Mycobacterium tuberculosis by the Mycobacteria Growth Indicator Tube (MGIT AST SIRE).

OBJECTIVE: To evaluate the reliability of the Mycobacteria Growth Indicator Tube (MGIT AST) for susceptibility testing of Mycobacterium tuberculosis. METHODS: Seventy strains of M. tuberculosis were tested for susceptibility to streptomycin, isoniazid, rifampicin and ethambutol by comparing MGIT AST results to those obtained by the method of proportion (MOP) on Lowenstein-Jensen (LJ) and Middlebrook 7H10 media. The 7H10 MOP was considered the method of reference. RESULTS: The turnaround time for MGIT AST was 6.2 days (5-10 days) and for MOP it was 18-21 days. With rifampicin, MGIT AST agreed for all isolates with both MOP. For streptomycin, MGIT AST and 7H10 MOP agreed for 64 isolates (91.4%); 61 were susceptible and three resistant. LJ MOP and 7H10 MOP agreed for 64 isolates (92.2%); 62 were susceptible and three resistant. With isoniazid, both MOP agreed for all isolates, while MGIT AST and 7H10 MOP had two discrepancies. For ethambutol, MGIT AST and 7H10 MOP were concordant for 66 isolates; 65 were susceptible and one resistant. Both MOP were concordant for 67 isolates; 66 were susceptible and one resistant. CONCLUSIONS: Based on these results, MGIT AST is a time-saving method and can be used as an alternative to the BACTEC System. MGIT AST is reliable as far as rifampicin and isoniazid are concerned; however, additional studies are needed for streptomycin and ethambutol.

Prevalence of methicillin-resistant Staphylococcus aureus in eight African hospitals and Malta.

Methicillin-resistant Staphylococcus aureus (MRSA) poses a serious therapeutic problem worldwide, and its frequency in most African countries has not been reported. This study was aimed at determining the prevalence and antibiotic susceptibility patterns of MRSA in eight large hospitals (>500 beds) in Africa and Malta, from 1996 to 1997. Susceptibility to methicillin (oxacillin) and to other drugs was determined by E test (AB Biodisk, Solna, Sweden) on a total of 1440 clinical isolates of S. aureus. Methicillin resistance was detected in 213 (15%) of the 1440 isolates tested. The rate of MRSA was relatively high in Nigeria, Kenya, and Cameroon (21-30%), and below 10% in Tunisia, Malta, and Algeria. All MRSA isolates were sensitive to vancomycin, with MICs 60%) of MRSA strains were multiresistant. There is a need to maintain surveillance and control of MRSA infections in Africa.

[Antibiotic sensitivity of Salmonella strains isolated in a pediatric population in Dakar. Research of beta-lactamase and plasmids]. / Sensibilité aux antibiotiques des souches de Salmonella isolées en milieu pédiatrique dakarois. Recherche de bêta-lactamase et de plasmides.

114 strains of Salmonella were isolated from many samples in the Pediatric Hospital (Hôpital d'Enfants Albert Royer) of Dakar between January 1985 and December 1991. The sensibility to antibiotics were tested, and we studied the production of beta-lactamase and the presence of plasmids in the resistant strains. 27 serovars of Salmonella were identified and Salmonella typhi predominates with 45%. Only 28% of the strains were susceptible to all of the antibiotics, and 17% were found multiresistant; 8% of the strains produce beta-lactamase and plasmids were found in 6 multiresistant strains.

[Importance of culture media choice in the isolation of Haemophilus ducreyi. Experience in Senegal]. / Importance du choix d'un milieu de culture dans l'isolement de Haemophilus ducreyi. Expérience du Sénégal.

Genital ulcerations typify one of the major reasons clients seek STD consultation in developing countries. The usual etiologies are syphilis, chancroid and herpes. The ideal diagnostic approach is to undertake complete laboratory examination that are rarely possible in structure destitute of laboratory analysis possibilities which is the case for most of the STD transmission agents. Chancroid is caused by Haemophilus ducreyi, a short Gram negative bacteria. The bacteriological diagnosis is based on direct examination, isolation and identification of the bacteria. The nutritive exigence of the bacteria required 3 medium of isolation (PPLO base Pasteur), GC base (GIBCO) and Muller Hinton base (Becton & Dickinson, with "chocolate" agar) have been tested from the chancre samples of 108 male patients who had a median age of 31 years. Direct exams were positive in 66 cases (61%) and culture exams positive in 53 cases (49%). The Muller Hinton base with "chocolate" agar produced the best results and seems to be the medium of choice for isolated strains in Senegal. The culture mediums currently used in Europe are apparently inappropriate for the germ culture in Senegal. We have also observed that all the isolated strains were producers of beta-lactamase. Antibiotic treatment before the sample swab is taken seems to have an inhibiting effect on the culture. Direct examination with a sensibility of 94.3% and a specificity of 70.9% remains sufficient in routine presumptive diagnosis in endemic areas.

[Improvement of tuberculosis diagnosis by the Mycobacteria Growth Indicator Tube (MGIT) in a developing country laboratory]. / Amélioration du diagnostic de la tuberculose par le Mycobacteria Growth Indicator tube (MGIT) dans un laboratoire de pays en développement.

In order to improve tuberculosis diagnosis in a developing country (Senegal), we evaluated a new liquid-based medium and nonradioactive system, Mycobacteria Growth Indicator Tube (MGIT), with individual clinical specimens collected in Dakar. The main purpose was to compare the time to detection and the rate of recovery of Mycobacterium tuberculosis complex and to determine its importance with respect to Lowenstein-Jensen (LJ), a liquid-based-medium for isolation of M. tuberculosis complex. 531 specimens were processed with Mycoprep kit containing NaOH-N-acetyl L-cystein and inoculated on both LJ and MGIT and incubated at 37 degrees C for 60 days. For each medium, the recovery rate and the time to detection were recorded. Among the 531 specimens, of which 121 smears were positive, 32.5% (173/531) grew the M. tuberculosis complex. Of these, 103 were smear positive (S+) and 70 smear negative (S-). LJ recovered 54.9% (95/173) and MGIT recovered 91.9% (159/173). Disagreements were observed with 92 isolates, LJ failed to recover 78 while MGIT failed to recover 14. The overall mean time to detection was 20.1 days for LJ and 10.5 days for MGIT. MGIT has shown a better sensitivity in isolation with significant reduction in reporting culture for M. tuberculosis complex. As a simple and a nonradiometric system, it could be used in conjunction with egg-based media in developing countries laboratories.

[Phenotypic differences of nosocomial bacterial strains isolated in the obstetric-gynecology service of the University Hospital Center of Dakar]. / Caractères phénotypiques de différentes souches bactériennes nosocomiales isolées au service de gynécologie-obstétrique du CHU de Dakar.

A study on nosocomial infections was conducted in the Laboratory of Bacteriology-Virology of Aristide Le Dantec's Hospital, in collaboration with the Gynecology Obstetrics clinic located both in the same Dakar's hospital, during May 1995. The aim of the study was to define the phenotypical characteristics of various bacterial strains isolated from the atmosphere health care staff's hands, medical equipment (material, antiseptics) and patients (hospitalized pregnant and newborns in day Nursery). A total of 133 strains were collected and the most frequent isolates were Staphylococcus aureus (27 strains) and Klebsiella pneumoniae (10 strains) encountered mainly in the atmosphere. Otherwise, Escherichia coli (11 strains) and Enterococcus faecalis (11 strains) were more present in hospitalized patients. Results obtained after antimicrobial agents susceptibility (Antibiotics and Heavy metal salts) by Antibiogramm and Minimal inhibitory concentrations (MIC) and also data from biotyping of Klebsiella strains have allowed us to say there's a probable contamination of hospitalized patients by the bacteria from the atmosphere but manuportage too.

[Neonatal bacterial infections at the CUH of Dakar]. / Infections bactériennes néonatales au CHU de Dakar.

OBJECTIVES: It's a retrospective study in order to determine the epidemiology of neonatal bacterial infection and to evaluate the efficiency of the antibiotic protocol in University Teaching Hospital in Dakar. MATERIAL AND METHODES: From January 1st 1997 to December 31st 1998 we have registered 7461 live births, samples of blood are taken from 2312 new-born baby and they received antibiotherapy (beta-lactamine + gentamycin) at the first day based on infections risk evaluated by anamnestic criterias. The treatment is seven to one days long, the antibiotic was adapted according to the antibiogram result. RESULTS: The neonatal infection diagnosis is confirmed in 246 cases, about 33 per 1000 live births or 10.6% of newborn babies having on antibiotherapy. Most current risk factors are premature rupture of membranes (85%) and neonatal suffering (87.8%). Isolated gerras are: Klebsiella pneumoniae (61.5%), Enterobacteria (11.5 Staphylococcus (8.7%), colibacille (6%), Streptococcus (5.5%), Enterococcus (4.1%) and Pseudomonas (2.7%). Most of these germs are resistant to antibiotics currently used in first intention (ampicillin, cefotaxim, gentamycin), in particularly 95% of Klebsiella. Most efficient antibiotics are amikacin, colistin, ceftriaxon and ciprofloxacine. Deaths occurs in 48 cases with 36 in early neonatal period, 79% of mortality rate related to infection by Klebsiella. CONCLUSION: First intention antibiotherapy must be always adapted to the bacterial ecology evolution and must be more selective by using major infections risk factors. We promote early infection diagnosis by using biologic markers which reference is represented by C Reactive Protein.

[Causes of infectious gastro-enteritis in children in Dakar]. / Causes des gastro-entérites infectieuses de l'enfant à Dakar.

Between February 1983 and May 1988, 1,157 stools from children aged under 15 years presenting with diarrhoea and admitted to a paediatric hospital in Dakar, Senegal, were examined for the presence of bacterial and parasitic agents. We looked for Campylobacter and rotavirus in only 245 and 111 samples respectively. Enterobacteria were detected most frequently (162/264; 61.3 per cent). Among these, we found 92 (34.8 per cent) strains of enteropathogenic E. coli; 40 strains (15.1 per cent) of Salmonella spp. and 30 strains (11.3 per cent) of Shigella spp. V. cholerae was present in only 2 faecal specimens (0,7 per cent). Eighty-one (30.6 per cent) parasitic agents were isolated, including a high proportion (13.6 per cent) of flagellae. Campylobacter jejuni and retroviruses were found in 2 (0.8 percent) and 15 (13.5 percent) stool respectively. The frequency with which these enteropathogenic agents were isolated remains in keeping with the global situation usually observed in Dakar for several years.

[Methicillin-resistant Staphylococcus aureus in Dakar]. / Staphylococcus aureus résistants à la méticilline à Dakar.

This study was carried out at the Fann University Hospital Center in Dakar, Senegal between 1994 and 1996. The purpose was to assess the prevalence of methicillin-resistant Staphylococcus aureus and to propose alternative treatments. A total of 149 stains of Staphylococcus aureus were isolated from a variety of clinical specimens. Sensitivity to various antibiotics was tested by the disc diffusion technique (anti-biogram). Resistance to methicillin was evaluated by the oxacillin disc diffusion technique on Mueller-Hinton agar containing 5% NaCl. The prevalence of methicillin resistance was 66.4%. All strains of Staphylococcus aureus were sensitive to vancomycin. Other highly effective antibiotics included fucidic acid (94%), aminoglycosides (91%), cotrimoxazol (89.6%), and norfloxacin (84.5%). Most strains (70.6%) presented a wide profile against macrolides and related groups. The LSa phenotype (resistance to lincosamines and streptogramines) was the predominant resistant phenotype. The results of this study indicate that the prevalence of methicillin-resistant Staphylococcus aureus is increasing in Senegal. Since these strains respond well to chloramphenicol and cotrimoxazole, clinicians are advised to use these drugs as an alternative first-line treatment.

[A new case of rhinoscleroma with skin extension]. / Un nouveau cas de rhinosclérome avec atteinte cutanée.

Scleroma is a chronic and specific granulomatous disease of bacterial origin. Klebsialla rhinoscleromatis, a gram-negative bacillus. The majority of cases affect the upper airways, particularly the nose, thus justifying the term of rhinoscleroma. Extension to the palate, the upper lip and the skin is possible. A new case of rhinoscleroma with skin extension is reported. To us, this is the second case in Senegal (Casamance). Epidemiological, clinical, bacteriological and histological aspects of the disease are reviewed. Under suitable antibiotic, evolution is currently favorable.

[Urinary bacteriology in the elderly in the tropical zone: results of 5 years of activities at the CHU of Fann in Dakar]. / Bactériologie des urines chez le sujet âgé en zone tropicale: bilan de cinq années d'activités au CHU de Fann à Dakar.

The authors report a retrospective account on 5 years (1987-1991) studied on 300 specimen of urine, coming from subjects aged 65 or more and having been submitted to bacteriologic examination in Dakar, Senegal (microscopic examination, counting, isolation, identification of bacteria, antibiotic tests). On the whole, 8150 samples of urine were recorded during the same period in the Laboratory of Bacteriology (CHU de Fann). The results obtained show a particular exposure of the old subjects to urinary tract infection (37%, against 23% in subjects aged less 65 years). The isolation of bacteria was not attached to sex. E. coli and Klebsiella sp. are the most frequently isolated in urine. The most efficacy antibiotics on these agents are the Cepholosporins, the Aminosids, Nitroxolin and Oxolonic Acid.

[Control of reproduction in the female Ndama cow by Norgestomet (CRESTAR)]. / Maîtrise de la reproduction de la femelle bovine Ndama par le Norgestomet (CRESTAR).

The purpose of this experiment was to test the efficiency of the Norgestomet CRESTARND on 91 Ndama cows living in three different ecological zones. The results of the experiments showed an average rate of heat synchronisation of 97.8%, an average heat time of 10.17 +/- 2.81 h with the intensity of these heat being essentially low or medium levels. The heats also occurred of mostly during the night. The time lag between the PGF2 alpha injection and the first signs of oestrus was 83.96 +/- 14.96 h and the one between removing the implant and the first heats was 34.78 +/- 14.9 h and the average blood's level of progesterone was 5 +/- 10.3 ng/ml. The efficiency of CRESTARND in the control of the sexual cycle of the Ndama cows was demonstrated by this study.

[Antibacterial activity of essential oils from mint in Senegal]. / Activité antibactérienne des huiles essentielles de menthes du Sénégal.

Three species of the Mentha gender are found in Senegal under the name of "Nana", and are essentially used in tea and juices as flavour. The aerial parts of the three species (common mint, mentholated mint and "fass" mint) have been harvested two months after they have been sown and the extraction of the essential oils was done by carrying them away with water vapour by hydrodistillation. The essential oils were used to study the antibacterial potency (typing of the Minimal Inhibitory concentrations-MIC) by the agar dilution method. This survey has been carried out on ten bacterial strains among which three (3) ATCC reference stubs, and on one fungus (Candida albicans). The MIC found was less than 25 mcg/ml; these results show an antibacterial potency according to the NCCLS norms (MIC < 256 mcg/ml). The tested strains were more sensitive to the essential oil of the "common mint" than the "fass mint". Pseudomonas aeruginosa was the most resistant strain and Candida albicans the most sensitive agent.

[Urinary infections in gyneco-obstetrical practice at DAKAR U.H.C]. / Les infections urinaires en pratique gynéco-obstétricale au C.H.U. de Dakar.

This prospective study seeks to define the epidemiological, clinical and biological boundaries of the danger of urinary infection in women, with a view to facilitating therapy where bacteriological competition is absent. 238 samples taken over a 4 month period revealed 57 bacteriologically positive, i.e. 24%. Urinary infection is particularly associated with women in their 30s, poor, and from a low socio-economic class, with little urinary history. Risk increases for pregnant women during the second quarter. Typical, classical symptoms, each for what it is worth, are to be found in over 75% of the positive samples. The most common germs are enterobacteria particularly sensitive to quinolones, aminosides and 3rd generation cephalosporines.

[Feasability of a heart valve bank in Dakar. (Preliminary study of 8 human hearts)]. / Faisabilité d'une banque d'homogreffes valvulaires cardiaque à Dakar. (Etude préliminaire sur 8 prélèvements de coeurs humains)

Authors record a preliminary study led so as to develope techniques of preparation of the cardiac homograft valves. Eight human hearts have been appropriated in the course of medico-legal autopsy. Under sterile hodd, the heart was dissected, aortic and pulmonary valves as well as a mitral valve fragment were collected for a total of 24 valvular levies. After sterlization in an antibiotic solution, valves were preserved at 4 degrees C for the mitral fragment specimen of fresh allograft and to - 196 degrees C in Nitrogen liquidates for the pulmonary and aortic valves. The control of graft quality had consisted in tests of competence during the dissection, to the evaluation of the histological study as well as tests of sterility. Cellular cultures had shown a fibroblast proliferation in 3 cases. It concerned an indeed reliable method but difficult and little sensitivity. Histological tests had shown two types of injurie: the myxoid degeneration (7 times on 8 valves) cryopreserved and a coagulative necrosis whose distribution was identical forthe two modes of conservation. Antibiotic's solution seemed to induce these injuries as do heart ischemia, and the traumatism lihleed to the great cold. The tests of sterility had shown a rate of contamination to 25 % essentially by Pseudomonas. In view of the installation of a behle of allograft bank of quality, we'll need to improve conditions of leavy, to use a freezer adaptation for progressive cryocongelation and the choice of simple method to evaluate valvular viabilty.