Bacteriological and molecular characterization of Mycobacterium bovis isolates from tuberculous lesions collected among slaughtered cattle, Northwest Ethiopia.

BACKGROUND: In Ethiopia, the distribution of bovine tuberculosis (BTB) has long been known and documented as a major problem of animal health. However, the burden of circulating M. bovis strains is poorly understood in the country. Therefore; this study aimed to identify and characterize the mycobacterial isolates responsible for BTB in Northwest Ethiopia. METHODS: A cross-sectional study was conducted on tuberculous lesions that had been collected from slaughtered cattle between September 2018 to June 2019. Collected lesions were cultured and tested for tuberculous bacilli. The MPT64 assay and Genotype line probe assay (LPA) were used for identification of mycobacterial isolates, and region of deletion 4 (RD4) typing and spoligotyping were used to characterize the M. bovis strains. RESULTS: Of the total 1458 examined slaughtered cattle, only 62 (4.3, 95%CI; 0.0328-0.0542) had tuberculous lesions. The highest number of gross tuberculous lesions were observed from the lymph nodes of the thoracic cavity; at the mediastinal (40.3%, 25/62) and bronchial (22.6%, 14/62) lymph nodes. Of the 62 collected tuberculous lesions; 18 (29.0%) were culture positive for mycobacterium isolates, and only five isolates were confirmed for M. tuberculosis complex (MTBc) by the MPT64 assay and LPA. All the five MTBc isolates were positive for RD4 typing of M. bovis with a PCR product size of 446 bp, and no isolate was noticed to have M. tuberculosis. The detected M. bovis strains displayed five spoligotypes; with the common SB1176 and SB0133 M. bovis strains, although the two spoligotypes had not been previously reported. CONCLUSION: The present study shows that BTB in North Gondar, Ethiopia, is caused by M. bovis strains SB1176 and SB0033, with low frequency. Thus, the finding highlights the importance of continuous surveillance for mycobacterial strains in cattle populations.

Nutritional status, intestinal parasite infection and allergy among school children in northwest Ethiopia.

BACKGROUND: Parasitic infections have been shown to have deleterious effects on host nutritional status. In addition, although helmintic infection can modulate the host inflammatory response directed against the parasite, a causal association between helminths and allergy remains uncertain. The present study was therefore designed to evaluate the relationship between nutritional status, parasite infection and prevalence of allergy among school children. METHODS: A cross sectional study was performed involving school children in two elementary schools in Gondar, Ethiopia. Nutritional status of these children was determined using anthropometric parameters (weight-for-age, height-for-age and BMI-for-age). Epi-Info software was used to calculate z-scores. Stool samples were examined using standard parasitological procedures. The serum IgE levels were quantified by total IgE ELISA kit following the manufacturer's instruction. RESULT: A total of 405 children (with mean age of 12.09.1 ± 2.54 years) completed a self-administered allergy questionnaire and provided stool samples for analysis. Overall prevalence of underweight, stunting and thinness/wasting was 15.1%, 25.2%, 8.9%, respectively. Of the total, 22.7% were found to be positive for intestinal parasites. The most prevalent intestinal parasite detected was Ascaris lumbricoides (31/405, 7.6%). There was no statistically significant association between prevalence of malnutrition and the prevalence of parasitic infections. Median total serum IgE level was 344 IU/ml (IQR 117-2076, n=80) and 610 IU/ml (143-1833, n=20), respectively, in children without and with intestinal parasite infection (Z=-0.198, P>0.8). The prevalence of self reported allergy among the subset was 8%. IgE concentration was not associated either with the presence of parasitic infection or history of allergy. CONCLUSION: The prevalence of malnutrition, intestinal parasitism and allergy was not negligible in this population. In addition, there was no significant association between the prevalence of allergy and their nutritional status, and parasite infection. Further research prospective observational and intervention studies are required to address the question of causality between nutritional factors, parasites, and allergy.

Micronutrient levels and nutritional status of school children living in Northwest Ethiopia.

BACKGROUND: Several micronutrients are essential for adequate growth of children. However, little information is available on multiple micronutrient status of school children in Ethiopia. The present study was designed to evaluate the relationship between multiple micronutrient levels and nutritional status among school children. METHOD: In this cross-sectional study, anthropometric data, blood and stool samples were collected from 100 children at Meseret Elementary School in Gondar town, Northwest Ethiopia. Serum concentration of magnesium, calcium, iron, copper, zinc, selenium and molybdenum were measured by inductively coupled plasma mass spectrometer. Anthropometric indices of weight-for-age, height-for-age and BMI-for-age were used to estimate the children's nutritional status. Stool samples were examined by standard microscopic methods for intestinal parasites. RESULTS: The prevalence of stunting, underweight, wasting and intestinal parasitoses among school children was 23%, 21%, 11% and 18%, respectively. The mean serum levels of magnesium, calcium, iron, copper, zinc, selenium and molybdenum were 2.42±0.32 (mg/dl), 15.31±2.14 (mg/dl), 328.19±148.91 (µg/dl), 191.30±50.17 (µg/dl), 86.40±42.40 (µg/dl), 6.32±2.59 (µg/dl), and 0.23±0.15 (µg/dl), respectively. Selenium deficiency, zinc deficiency and magnesium deficiency occurred in 62%, 47%, and 2% of the school children, respectively. Height-for-age showed significant positive correlation with the levels of copper and molybdenum (p = 0.01) and with the levels of magnesium (p = 0.05). CONCLUSION: Deficiencies of selenium and zinc were high among the school children although the deficiencies were not significantly related with their nutritional status. The prevalence of both malnutrition and intestinal parasitism was not negligible. These calls for the need to undertake multicentre studies in various parts of the country to substantiate the data obtained in the present study so that appropriate and beneficial strategies for micronutrient supplementation and interventions on nutritional deficiencies can be planned.

Vitamin A deficiency during pregnancy of HIV infected and non-infected women in tropical settings of Northwest Ethiopia.

BACKGROUND: Vitamin A deficiency (VAD) is known to be a major public health problem among women of reproductive age in South East Asia and Africa. In Ethiopia, there are no studies conducted on serum vitamin A status of HIV-infected pregnant women. Therefore, the present study was aimed at determining the level of serum vitamin A and VAD among pregnant women with and without HIV infection in tropical settings of Northwest Ethiopia. METHODS: In this cross-sectional study, blood samples were collected from 423 pregnant women and from 55 healthy volunteers who visited the University of Gondar Hospital. Serum concentration of vitamin A was measured by high performance liquid chromatography. RESULTS: After controlling for total serum protein, albumin and demographic variables, the mean ± SD serum vitamin A in HIV seropositive pregnant women (0.96 ± 0.42 µmol/L) was significantly lower than that in pregnant women without HIV infection (1.10 ± 0.45 µmol/L, P < 0.05). Likewise, the level of serum vitamin A in HIV seropositive non-pregnant women (0.74 ± 0.39) was significantly lower than that in HIV negative non-pregnant women (1.18 ± 0.59 µmol/L, P < 0.004). VAD (serum retinol < 0.7 µmol/L) was observed in 18.4% and 17.7% of HIV infected and uninfected pregnant women, respectively. Forty six percent of non-pregnant women with HIV infection had VAD while only 28% controls were deficient for vitamin A (P = 0.002). CONCLUSION: The present study shows that VAD is a major public health problem among pregnant women in the tropical settings of Northwest Ethiopia. Considering the possible implications of VAD during pregnancy, we recommend multivitamin (which has a lower level of vitamin A) supplementation in the care and management of pregnant women with or without HIV infection.

Occurrence, seasonality and genetic diversity of Vibrio vulnificus in coastal seaweeds and water along the Kii Channel, Japan.

Vibrio vulnificus is a ubiquitous toxigenic bacterium found in a coastal environment but little is known about its occurrence and seasonality among seaweeds, which are widely consumed as seafood in Japan. Therefore, we have observed the bacterium's abundance in seawater and seaweed samples from three areas of the Kii Channel, Japan, during June 2003 to May 2004. A total of 192 samples were collected: 24 from each source in summer, autumn, winter and spring. The samples were selectively cultivated following the most probable number (MPN) technique. Vibrio vulnificus population ranged from 0 to 10(3) MPN 100 mL(-1) seawater or 10 g seaweeds; higher counts were observed during summer. The optimum temperature, salinity and pH for the bacterium were 20-24 degrees C, 24-28 p.p.t. and 7.95-8.15, respectively. However, seaweeds always contained higher V. vulnificus than seawater. Among 280 V. vulnificus strains, detected by species-specific colony hybridization and PCR, 78, 74, 11 and 16 were from seaweeds and 46, 42, 2 and 11 were from seawater during summer, autumn, winter and spring, respectively. Ribotyping of 160 selected strains revealed a higher genotypic diversity (18 patterns) among strains from seaweeds than from seawater (10 patterns). Seaweeds can thus act as a potential habitat for V. vulnificus and are more unsafe for consumption during summer.

Serum zinc, copper, selenium, calcium, and magnesium levels in pregnant and non-pregnant women in Gondar, Northwest Ethiopia.

Pregnant women in developing countries are vulnerable to multiple micronutrient deficiencies. Studies assessing serum levels of the micronutrients and magnitude of their deficiencies are very scarce in African subjects. This study was aimed at determining serum levels of micronutrients in 375 pregnant (42 HIV seropositive) and 76 non-pregnant women (20 HIV seropositive) who visited the University of Gondar Hospital, Gondar, Ethiopia. Serum concentrations of zinc,\ copper, selenium, calcium, and magnesium were determined using an inductively coupled plasma mass spectrometer. Irrespective of HIV serostatus, pregnant women had significantly higher serum concentrations of copper and copper/zinc ratio and significantly lower magnesium compared to those in non-pregnant women (P < 0.05). Except for selenium, which was significantly lower in HIV-seropositive pregnant women (P < 0.05), the mean serum concentrations of zinc, copper, calcium, and magnesium were not significantly different between pregnant women by HIV serostatus. The prevalence of deficiency in zinc, magnesium, selenium, and calcium in the pregnant women, irrespective of their HIV serostatus, was 66.7%, 25.6%, 21.9%, and 9.3%, respectively. The magnitude of deficiency in zinc, magnesium, and selenium was significantly higher in HIV seropositive pregnant women (76.2%, 52.4%, and 45.2%) than that in HIV-seronegative pregnant women (65.5%, 22.2%, and 18.9%) and in HIV-seronegative non-pregnant women (42.9%, 8.1%, and 30.4%; P < 0.05). Deficiency in one, two, three, or four mineral elements was observed in 44.8%, 14.4%, 9.9%, and 5.1% of the pregnant women, respectively. Only 25.9% of the pregnant women and 44.7% of the non-pregnant women were not deficient in any of the micronutrients. The high prevalence of micronutrient deficiencies in pregnant and non-pregnant women in Gondar, Ethiopia warrants the need for strategies on prevention and control of the deficiencies.

Molecular epidemiology of HIV type 1 in treatment-naive patients in north Ethiopia.

To understand the predominant HIV subtype and drug-resistant viruses in northwest Ethiopia, isolates from 92 antiretroviral drug-naive HIV-1-infected tuberculosis patients were analyzed. Of these patients, 90 (97.8%) were found to be infected with viral subtype C. Other isolates had subtype A (1.1%) and subtype D (1.1%). No primary mutations were associated with protease inhibitor drug resistance. One case (1.1%) had the reverse-transcriptase mutation, V75I. Two patients (2.2%) had the G190A mutation, which confers resistance to the nonnucleoside reverse transcriptase inhibitor, nevirapine. Our study demonstrates that subtype C is the major HIV-1 subtype in northwest Ethiopia. Our results also reveal that the population in the study area had been exposed to antiretrovirals and that treatment-naive patients had drug resistance mutations. Thus, our results emphasize the need for routine drug resistance monitoring in northwest Ethiopia.

Seaweeds as a reservoir for diverse Vibrio parahaemolyticus populations in Japan.

Gastroenteritis caused by Vibrio parahaemolyticus has recently been associated with foods prepared with seaweeds, but little is known about the bacterium's abundance and diversity among seaweeds in coastal environment. Therefore, we determined its phenotypic and genotypic diversity in relation to its seasonal abundance in seawater and seaweed samples from three areas of Kii Channel, Japan during June 2003 to May 2004. Isolates were obtained by selective enrichment of samples and detection of V. parahaemolyticus by colony hybridization with a species-specific probe. A total of 128 isolates comprising 16 from each source in each season were characterized by serotyping and ribotyping. V. parahaemolyticus was more abundant in seaweeds (3,762 isolates) than in water samples (2,238 isolates). Twenty and 17 serotypes were found among the selected seaweed and seawater isolates, respectively. Cluster analysis revealed 19, 11, 7 and 9 ribotypes during summer, autumn, winter and spring, respectively. Seaweeds supported a diverse V. parahaemolyticus population throughout the year and thus seaweeds are a reservoir for the organism. However, V. parahaemolyticus occurrence had positive correlation with water temperature and its abundance in seaweeds was at least 50 times higher during summer than in winter.

Immune response to ovalbumin following bisphenol A administration in mice fed with a low level of dietary protein.

BACKGROUND AND PURPOSE: We have previously shown that bisphenol A (BPA) augments T-helper (Th) 1 activity with no significant effects on an established oral tolerance to ovalbumin (OVA) in mice fed with a normal protein diet. The present study aimed to examine the effect of BPA on the immune response in a mouse model maintained on a very low protein diet (5% casein). METHODS: Mice were fed on a 5% protein diet, together with either OVA (OVA-fed) or water (water-fed), immunized intraperitoneally with OVA at 3-week intervals and administered BPA between the 2 immunizations. A week after the last immunization, animals were sacrificed and examined by enzyme-linked immunosorbent assay for serum titers of total immunoglobulin E (IgE), OVA-specific IgE, immunoglobulin G (IgG), IgG1, IgG2a, and the production of interferon-gamma, interleukin (IL)-4, and IL-12. RESULTS: In both BPA-treated and non-treated animals, OVA feeding resulted in lower titers of total and OVA-specific IgE, and OVA-specific IgG (p<0.05). There were higher levels of interferon-gamma (p<0.05), IL-4, and IL-12 (p<0.05) in animals with OVA tolerance following BPA treatment. However, IL-12 production was augmented only in BPA-treated water-fed animals (p<0.01). CONCLUSION: BPA administration in mice fed with a low level of dietary protein augmented Th1 cytokines more profoundly in the animals with OVA tolerance than in the non-tolerant animals.

Coinfection and clinical manifestations of tuberculosis in human immunodeficiency virus-infected and -uninfected adults at a teaching hospital, northwest Ethiopia.

BACKGROUND AND PURPOSE: The pattern of clinical presentations of tuberculosis (TB) is reflected in the microbiological, radiological, and histological characteristics of the disease. However, coinfection with human immunodeficiency virus (HIV) poses special diagnostic and therapeutic challenges. This study was aimed at assessing the clinical manifestations of TB in patients with or without HIV coinfection in a hospital-based cross-sectional study in Gondar, Ethiopia. METHODS: TB was diagnosed following standard clinical, bacteriological, radiological, and histological procedures. HIV serostatus was checked by enzyme-linked immunosorbent assay. RESULTS: This study included 257 TB patients, of whom 52.1% were coinfected with HIV. Pulmonary TB and extrapulmonary TB were diagnosed in 64.2% and 35.8% of the patients, respectively. No significant association was found between sputum smear positivity and HIV serostatus. One-fifth of the patients reported hemoptysis. More than one-third had chest pain, and >90% reported fever and weight loss. Night sweats and cough were reported by 86% and 82.5%, respectively. Coarse crepitations were the most frequent auscultatory finding (33.9%). Sputum smear positivity rate was 26.8%. Cavitation was significantly associated with sputum smear positivity (odds ratio = 9.0, 95% confidence interval = 2.4-34.1). Wasting, cough of

Seroprevalence of syphilis and HIV-1 during pregnancy in a teaching hospital in northwest Ethiopia.

Ethiopia is one of the countries in which sexually transmitted infections are highly prevalent. However, the data needed to present a realistic picture of the infections are lacking. This study was therefore designed to determine the seroprevalence of syphilis and HIV-1 among pregnant women at the University of Gondar Teaching Hospital. A prospective cross-sectional hospital-based study was conducted between March and June, 2005. Blood samples were collected from 480 pregnant women attending the antenatal clinic of the hospital. Sera were tested for syphilis using the Rapid Plasma Regain (RPR) and Treponema pallidum hemagglutination (TPHA) kits, and serostatus for HIV infection was checked using rapid HIV diagnostic test kits following the manufacturers' instructions. The mean (+/-SD) age of the study participants was 26.1 (+/-7.2) years. The seroprevalence of syphilis was 1%. Antibodies against HIV-1 were detected in 9.6% of the pregnant women. A higher HIV-1 prevalence (13%) was observed in the 25- to 29-year-old age group followed by the 30- to 34-year-old age group (10.2%). Only one subject (2.2%) was found to be positive for both HIV-1 and syphilis. The data indicated a relatively declined prevalence of syphilis and HIV-1 among pregnant women in an urban antenatal clinic. However, incidence and behavioral studies are required to substantiate the findings.

HIV and intestinal parasites in adult TB patients in a teaching hospital in Northwest Ethiopia.

The level of HIV infection and intestinal parasitoses among TB patients was assessed in a hospital-based cross-sectional study involving 257 patients in Gondar, Ethiopia. In TB patients, our study reported co-infection with HIV (52.1%) and intestinal parasites (40.9%) The high prevalence of HIV and intestinal parasites indicates an increased morbidity inTB patients and emphasized the importance of continued HIV sero-surveillance, stool analysis and treatment.

Altered allergic cytokine and antibody response in mice treated with Bisphenol A.

The objective of this study was to elucidate if Bisphenol A (BPA) administration modulates T helper (Th) cell component of immune responses in a mouse challenged with ovalbumin (OVA), a major food antigen. BALB/c mice, (6 weeks old, female) were orally given either OVA (OVA-fed) or water (Water-fed), immunized intraperitoneally with OVA and injected with either BPA in corn oil or the vehicle alone. After subsequent 2nd immunization, serum titers of total IgE, OVA-specific IgE, IgG, IgG1 IgG2a and ability of their splenocytes for production of interferon (IFN) -gamma, interleukin (IL) -4 and IL-12 were examined by ELISA. Lymphocyte proliferation assay against concanavalin A (Con A) or OVA was also performed for 3H-Thymidine incorporation. In Water-fed groups, treatment with BPA resulted in lower titers of total IgE (P<0.01) and higher levels IgG2a (P<0.05) followed by a higher IFN-gamma (P<0.05) and IL-12 (P<0.05) with an intact IL-4. When OVA-fed groups were examined, the compound did not change production of total and OVA-specific IgE and -IgG2a but resulted in lower production of IFN-gamma (P<0.05). Also, BPA resulted in impaired lymphocyte proliferation to Con A in Water-fed groups (P<0.05) but not in tolerated animals. The findings indicate that BPA results in augmentation of Th1 immune responses but no significant effect on an established tolerance to OVA.

Seroprevalence of Helicobacter pylori in dyspeptic patients and its relationship with HIV infection, ABO blood groups and life style in a university hospital, Northwest Ethiopia.

AIM: To determine the prevalence of Helicobacter pylori (H pylori) among dyspeptic patients and to assess the relationship between H pylori infection, blood group, HIV infection and life style of the patients. METHODS: In a hospital-based cross-sectional study, patients attending Outpatient Department of University of Gondar Hospital were enrolled. Socio-demographic information was collected using questionnaires. Serum was analyzed for anti-H pylori IgG antibodies using a commercial kit. HIV serostatus was determined by enzyme-linked immunosorbent assay (ELISA). Blood grouping was performed by slide agglutination tests. RESULTS: A total of 215 dyspeptic patients were included in the study. One hundred and sixteen patients (54%) were females and 99 (46%) were males. Anti-H pylori IgG antibodies were detected in sera of 184 (85.6%) patients. The prevalence was significantly higher in patients aged 50 years and above. Twenty point five percent of the patients were found to be seropositive for HIV. No significant association was found between sex, ABO blood groups, consumption of spicy diets, socio-economic status and seropositivity for H pylori. However, alcohol consumption was significantly associated with H pylori serology. CONCLUSION: The prevalence of H pylori infection is associated with a history of alcohol intake and older age. The effect of different diet, alcohol and socioeconomic status as risk factors for H pylori infection needs further study.

Isolation and molecular characterization of toxigenic Vibrio parahaemolyticus from the Kii Channel, Japan.

Studies were conducted on the ecology of potentially pathogenic Vibrio parahaemolyticus in three coastal areas of Kii Channel, Tokushima, Japan. Seawater and seaweed samples were collected seasonally between June 2003 and May 2004. Total and toxigenic strains of V. parahaemolyticus were isolated using most probable number culture and colony blot hybridization. Toxigenic strains were serotyped and further characterized by random amplified polymorphic DNA (RAPD) and ribotyping. Six thousand strains of V. parahaemolyticus were isolated and 18 were found positive for tdh. V. parahaemolyticus were detected in all samples during summer and autumn, and from some samples during winter and spring. Among the toxigenic strains seven serotypes, five ribotypes and RAPD patterns were observed. Seven strains belonged to O3:K6 clone with identical ribotypes and RAPD patterns to that of a pandemic reference strain. The presence of toxigenic V. parahaemolyticus with pandemic potential might indicate a human health risk due to consumption of marine food sources.

Modulation of oral tolerance to ovalbumin by dietary protein in mice.

This study sought to determine whether oral tolerance to ovalbumin (OVA), responsible for food allergy, is affected by different amounts of protein intake. For this, 6-wk-old BALB/c mice were fed with low protein (5%, LP), normal protein (20%, NP) and high protein (40%, HP) diets, orally given either OVA (OVA-fed) or water (Water-fed) for 4 d, and then immunized intraperitoneally twice at a 3-wk interval with alum-precipitated OVA. After the last immunization, sera were collected to measure total and OVA-specific IgE by enzyme assay (ELISA). Splenocytes were cultured and stimulated with concanavalin A (Con A), lipopolysaccharide (LPS) or OVA and assayed for 3H-thymidine incorporation. The culture supernatants from their splenocytes stimulated with OVA were analyzed for interleukin (IL)-4, interferon (IFN)-gamma, and IL-12. Total IgE was significantly higher in OVA-fed HP groups as compared to NP and LP groups (p<0.05). The highest and the lowest OVA-specific IgE were observed in HP and LP diet groups, respectively (p<0.05). OVA-fed mice receiving the LP diet demonstrated significantly lower IL-4 as compared to the other two groups (p<0.05), while IFN-gamma was significantly higher in the LP compared to the HP group (p<0.05). Levels of IL-12 did not differ among the OVA-fed groups. Splenocytes of OVA-fed mice kept on the LP and HP diet showed significant impairment of proliferation to OVA as compared to the NP group (p<0.01). Proliferation against Con A was impaired in the LP group compared to the NP group (p<0.05) but not in Water-fed groups. However, it was higher against LPS in the HP than the LP group (p<0.05) both in Water-fed and OVA-fed animals. All these findings indicate that established oral tolerance to OVA is clearly affected by the amount of protein diet. They support the suggestion that dietary protein plays an important role(s) in IgE-mediated food allergies.

Antibacterial activity of citrus fruit juices against Vibrio species.

Lemon, lime and sudachi juices were tested for antibacterial activity against seven strains of Vibrio species. All juices were effective in inhibiting the growth of the Vibrio strains. Citric acid, the major organic acid in these juices, was found to be responsible for inhibiting the growth of Vibrio parahaemolyticus. Sauce prepared from sudachi juice showed a strong bactericidal activity against Vibrio parahaemolyticus, whereas the sauce adjusted to higher pH values had no bacterial activity. Diluted sudachi juice or citric acid solution also had antibacterial activity independently. These results suggest that citrus fruit juices are effective in preventing infection with Vibrio species.

Serum levels of trace elements and iron-deficiency anemia in adult Vietnamese.

This study was aimed at assessing the serum levels of vitamin A, copper, zinc, selenium, and iron among adult Vietnamese with and without iron-deficiency anemia. Blood was collected from adult Vietnamese living in the midland of northern Vietnam. One hundred twenty-three subjects in the age range 20-60 yr were included in the study. Anemia, where the concentration of hemoglobin in whole blood is less than 120 g/L in females and 130 g/L in males, was found in 30% (37/123) of the study population. The levels of vitamin Aand selenium in the sera of anemic subjects (n = 37) were significantly lower than that in nonanemic group (n = 86). On the other hand, no significant differences were observed in the concentrations of copper and zinc between the two groups. This study was the first to show serum levels of trace elements in adult Vietnamese, providing useful baseline information for further studies.

Seroprevalence of human immunodeficiency virus among blood donors in Northwest Ethiopia, 1995-2002.

Data on age, sex, occupation, HIV serostatus and year of donation were collected from the blood donors log book of Gondar College of Medical Sciences Hospital, Northwest Ethiopia, for the period between January 1995 and December 2002 and analysed. The crude HIV seroprevalence was 9.9% (1109/11,204). A declining trend in the prevalence was observed from as high as 15.7% (207/1321) in 1995 to 9.3% (123/1327) in 1999 and down to 4.3% (68/1576) in 2002. The declining trend observed in recent years is encouraging and should further be strengthened by making use of the blood bank as an entry point for HIV testing and counselling services.

Degradation of bradykinin by a metalloendopeptidase from Streptococcus pyogenes.

OBJECTIVES: Streptococcus pyogenes secretes streptococcal pyrogenic exotoxin B (SpeB), which cleaves kininogen to liberate bradykinin. In addition, this bacterium also has cell-associated bradykinin-degrading activity. Here, we characterized the bradykinin-degrading enzyme produced by S. pyogenes. METHODS: The effects of various peptidase inhibitors on bradykinin degradation by intact S. pyogenes and cell lysates were assessed. Cleavage of bradykinin and other peptides by a recombinant putative metalloendopeptidase (Sp-Pep) from S. pyogenes was analyzed by mass spectrometry. The enhancement of vascular permeability induced by bradykinin (before and after treatment with Sp-Pep) was evaluated in guinea pig skin. RESULTS: Various S. pyogenes strains expressed Sp-Pep. Immunoadsorption of S. pyogenes with an anti-Sp-Pep antibody showed that 80% of the bradykinin-degrading activity in S. pyogenes was due to Sp-Pep. Recombinant Sp-Pep cleaved bradykinin, and cleavage caused a loss of its extravasation-inducing potential. Sp-Pep-mediated degradation of bradykinin was 40 times more efficient than degradation of substance P and angiotensin II. While S. pyogenes secreted mature SpeB in stationary phase, this bacterium produced Sp-Pep during all tested growth phases. CONCLUSIONS: S. pyogenes produces a cell-associated metalloendopeptidase that degrades bradykinin.