Heavy metals and potential health risk assessment of Lactuca sativa and Daucus carrota from soil treated with organic manures and chemical fertilizer.

The large-scale production of food crops with heavy application of chemical fertilizers in the effort to meet the astronomical increase in food demands may be counterproductive to the goal of food security. This study investigated the effect of different soil treatments on the levels of heavy metals (Cr, Cu, Fe, Ni, Pb, and Zn) in two types of vegetables Lactuca sativa (lettuce) and Daucus carrota (carrot). The potential carcinogenic and non-carcinogenic health risks from their consumption were also evaluated. Planting experiment was set up in a randomized block design, with different soil treatments of soil + cow dung (CD), soil + sewage sludge (SS), soil + chemical fertilizer (nitrogen-phosphorus-potassium (NPK)), and untreated soil (UNTRD). The vegetables were harvested at maturity, washed with distilled water, and subjected to an acid digestion process before the levels of heavy metals were measured by inductively coupled plasma spectrometry (ICP-MS). The mean concentrations of the metals in the vegetables across all treatments were below the maximum permissible limits. The pattern of heavy metal accumulation by the vegetables suggested that the lettuce from SS treatment accumulated higher concentrations of heavy metals like Cr (0.20 mg/kg), Cu (3.91 mg/kg), Ni (0.33 mg/kg), and Zn (20.44 mg/kg) than carrot, with highest concentrations of Fe (90.89 mg/kg) and Pb (0.16 mg/kg) recorded in lettuce from NPK treatment. The bioaccumulation factor (BAF) showed that lettuce, a leafy vegetable, has bioaccumulated more heavy metals than carrot, a root vegetable. The BAF was generally below the threshold value of 1 in both vegetables, except in lettuce from NPK and CD treatments and carrot from NPK treatments, with BAF values of 1.6, 1.69, and 1.39, respectively. The cancer risk assessment factors were well below the unacceptable maximum range of 10-4 suggesting that consuming these vegetables might not expose an individual to potential risk of cancer development. The hazard quotient estimations were below the threshold values of 1 for all heavy metals; however, the hazard index (HI) values of 1.27 and 1.58 for lettuce from NPK and SS treatments indicate a potential non-carcinogenic health risk to consumers from intake of all the heavy metals.

Mixed Aetiology of Diarrhoea in Infants Attending Clinics in the North-West Province of South Africa: Potential for Sub-Optimal Treatment.

Routine diagnostic methods for the aetiologic agents of diarrhoea in most developing countries are usually not sensitive enough, leading to under-diagnosis. Thus, this study investigated possible mixed diarrhoeal aetiology by using cultures and real-time polymerase chain reactions (PCR) in children younger than four years old in the Northwest Province, South Africa. In total, 505 stool samples were collected from symptomatic and asymptomatic children who were attending three clinics and the Brits hospital in Madibeng District, between September 2016 and December 2017. Rotavirus, norovirus, Campylobacter, Arcobacter, and diarrhoeagenic Escherichia coli (DEC) were targeted. Campylobacter spp. (24.6%), Arcobacter (15.8%) and DEC (19.6%) were detected using PCR; only Campylobacter spp. (29.7%) and DEC (26.9%) were detected through the culture. Campylobacter jejuni (36%), Campylobacter coli (28%), Campylobacter upsalensis (12%), and Arcobacter butzleri (15.8%) were the only spp. of Campylobacter and Arcobacter identified. The eaeA gene (31.4%) of enteropathogenic E. coli/enterohaemorrhagic E. coli (EPEC/EHEC) was the most prevalent DEC virulence gene (VG) identified. Rotavirus and norovirus were detected at 23.4% and 20%, respectively. Mixed viral aetiology (7.3%) and the co-infection of A. butzleri and Campylobacter (49%) were recorded. A mixed bacterial-viral aetiology was observed in 0.6% of the specimens. Sensitive diagnostic procedures like PCR should be considered to provide the best treatment to children experiencing diarrhoea.

Novel Mycobacterium avium Complex Species Isolated From Black Wildebeest (Connochaetes gnou) in South Africa.

A study was undertaken to isolate and characterize Mycobacterium species from black wildebeest suspected of being infected with tuberculosis in South Africa. This led to the discovery of a new Mycobacterium avium complex species, provisionally referred to as the Gnou isolate from black wildebeest (Connochaetes gnou). Sixteen samples from nine black wildebeest were processed for Mycobacterium isolation. Following decontamination, samples were incubated in an ordinary incubator at 37°C on Löwenstein-Jensen slants and in liquid medium tubes using the BACTEC™ MGIT™ 960 system, respectively. Identification of the isolate was carried out by standard biochemical tests and using the line probe assay from the GenoType® CM/AS kit (Hain Lifescience GmbH, Nehren, Germany). The DNA extract was also analysed using gene sequencing. Partial gene sequencing and analysis of 16S rRNA gene, and 16S-23S rRNA (ITS), rpoB and hsp65 and phylogenetic analyses by searching GenBank using the BLAST algorithm were conducted. Phylogenetic trees were constructed using four methods, namely Bayesian inference, maximum likelihood, maximum parsimony and neighbour-joining methods. The isolate was identified as Mycobacterium intracellulare using the GenoType® CM/AS kit and as Mycobacterium avium complex (MAC) by gene sequencing. The gene sequence targeting all the genes, ITS, 16S rRNA, rpoB and hsp65 and phylogenetic analyses indicated that this isolate presented a nucleotide sequence different from all currently published sequences, and its position was far enough from other MAC species to suggest that it might be a new species.

Diversity and antibiograms of bacterial organisms isolated from samples of household drinking-water consumed by HIV-positive individuals in rural settings, South Africa.

Diarrhoea is a hallmark of HIV infections in developing countries, and many diarrhoea-causing agents are often transmitted through water. The objective of the study was to determine the diversity and antibiotic susceptibility profiles of bacterial organisms isolated from samples of household drinking-water consumed by HIV-infected and AIDS patients. In the present study, household water stored for use by HIV-positive patients was tested for microbial quality, and isolated bacterial organisms were analyzed for their susceptibility profiles against 25 different antibiotics. The microbial quality of water was generally poor, and about 58% of water samples (n=270) were contaminated with faecal coliforms, with counts varying from 2 colony-forming unit (CFU)/100 mL to 2.4x104 CFU/100 mL. Values of total coliform counts ranged from 17 CFU/100 mL to 7.9x105/100 mL. In total, 37 different bacterial species were isolated, and the major isolates included Acinetobacter lwoffii (7.5%), Enterobacter cloacae (7.5%), Shigella spp. (14.2%), Yersinia enterocolitica (6.7%), and Pseudomonas spp. (16.3%). No Vibrio cholerae could be isolated; however, V. fluvialis was isolated from three water samples. The isolated organisms were highly resistant to cefazolin (83.5%), cefoxitin (69.2%), ampicillin (66.4%), and cefuroxime (66.2%). Intermediate resistance was observed against gentamicin (10.6%), cefepime (13.4%), ceftriaxone (27.6%), and cefotaxime (29.9%). Levofloxacin (0.7%), ceftazidime (2.2%), meropenem (3%), and ciprofloxacin (3.7%) were the most active antibiotics against all the microorganisms, with all recording less than 5% resistance. Multiple drug resistance was very common, and 78% of the organisms were resistant to three or more antibiotics. Education on treatment of household water is advised for HIV-positive patients, and measures should be taken to improve point-of-use water treatment as immunosuppressed individuals would be more susceptible to opportunistic infections.

Random amplified polymorphic DNA typing of clinical and environmental Aeromonas hydrophila strains from Limpopo province, South Africa.

The aim of the present study was to determine the genetic relatedness of strains isolated from diarrhoeal stool and water specimens collected from water-storage containers from different geographical areas in the Limpopo province. In total, 32 Aeromonas strains isolated from stool specimens collected from HIV/AIDS patients suffering from gastroenteritis and their household drinking-water stored in 20-L and 25-L containers were analyzed by random amplified polymorphic DNA PCR (RAPD). The RAPD fingerprints obtained proved reproducible when repeated on three different occasions using whole-cell DNA isolated from the Aeromonas strains. In total, 12 unique RAPD fingerprints were found. The results revealed a tendency of the isolates to cluster according to their origin of isolation (best-cut test 0.80 and bootstrap values >50%). However, a certain degree of similarity was also observed between isolates of water sources and clinical sources which indicated genetic relatedness. There were also genetic similarities between the clinical and the environmental strains of Aeromonas spp. isolated from different geographical areas. This study has demonstrated the genetic relatedness of Aeromonas hydrophila isolates from household drinking-water and clinical sources in South Africa, which may be due to cross-contamination from water to patients or vice-versa. This observation is of public-health significance, particularly in the era of HIV/AIDS. This study points to the importance of monitoring and evaluating infection-control measures for improved hygiene and to prevent cross-contaminations.

Drug-susceptibility patterns of Mycobacterium tuberculosis in Mpumalanga province, South Africa: possible guiding design of retreatment regimen.

Multidrug-resistant tuberculosis (MDR-TB) has been a cause of concern in both developed and developing countries. The prevalence of drug resistance in Mycobacterium tuberculosis (MTB) isolates (n=692) from Mpumalanga province was assessed. In total, 692 (64%) MTB strains from cases with pulmonary TB were tested for susceptibility against rifampicin, isoniazid, ethambutol, and streptomycin using the MGIT 960 instrument. Two hundred and nine (30.2%) strains were resistant to one or more drugs. Resistance to one drug ranged from 1.4% for ethambutol to 17.7% for rifampicin. The prevalence of MDR-TB ranged from 6.7% for three drugs to 34% for four drugs, with significant predictors being patients' age-groups of 25-54 years (p=0.0012) and >55 years (p=0.007). The result showed a high level (58.4%) of MDR-TB from cases in Mpumalanga province. To achieve a higher cure rate in this province, drug-susceptibility tests must be done for every case.

Sexual health dialogue between parents and teenagers: an imperative in the HIV/AIDS era.

Societies are reluctant to openly confront issues of sexuality, and this reluctance forms a barrier of communication between parents and teenagers and even between sexual partners (Wulf, 2004:2). This reluctance promotes the presence of misconceptions about sexual health, sexual risks and its consequences. Poor dialogue about sexual health between parents and teenagers is one of the contributory factors of high teenage pregnancy and sexually transmitted infection (STI) rates including HIV and AIDS. The purpose of this study was to explore and describe how dialogue about sexual health between teenagers and parents is conducted and to use the information gathered as a basis for making recommendations for improvement. A qualitative study of an explorative, descriptive and contextual nature was used. The researcher used the main question as a point of departure and more questions emanated from the discussions. There were 42 informants involved in the study, of which 4 were males and 38 were females. A purposive sampling method was used to collect data through in depth individual interviews and focus group discussions. The researcher strived to adhere to the principle of trustworthiness by adopting Guba's model (in Krefting, 1991: 217). Tech's method (Creswell, 1994:154-55) was used to analyse the data and an independent coder was used. The results indicate that there is minimal if not absent dialogue about sexual health between teenagers and parents. Culture was identified as a major challenge to sexual health dialogue between teenagers and parents. Recommendations to enhance dialogue were made.

In-vitro cytotoxicity and antimicrobial activities, against clinical isolates of Campylobacter species and Entamoeba histolytica, of local medicinal plants from the Venda region, in South Africa.

In the quest for alternative treatments against Campylobacter jejuni and Entamoeba histolytica, which are both aetiological agents of diarrhoea world-wide, the in-vitro activities against the two pathogens of extracts of 18 South African medicinal plants have recently been assessed. Forty extracts from the 18 plant species were prepared and tested against 110 clinical isolates of Campylobacter spp. In addition, extracts from eight of the plant species were tested against a standard strain (HM-1:IMSS) of E. histolytica, and the cytotoxicity of each of 19 extracts from 15 of the plant species was explored using Vero cell cultures and microdilution assays. At least one extract of each plant species investigated was found to be active against some of the Campylobacter isolates. Extracts of Lippia javanica and Pterocarpus angolensis had the highest antibacterial activity, each giving a minimum inhibitory concentration (MIC) of 90 microg/ml. Of the extracts tested against E. histolytica, however, only those of P. angolensis and Syzigium cordatum were found to have anti-amoebic activity, with MIC of 1.2 and 7.5 mg/ml, respectively. Although most of the extracts showed little toxicity against Vero cells, with most of the median inhibitory concentrations (IC(50)) recorded exceeding 400 microg/ml, an extract of Bauhinia galpini was quite toxic, with an IC(50) of just 2.7 microg/ml. Acetone and methanol extracts of several of the plants show promise as templates for the design of new anti-diarrhoeal therapies.

Prevalence of intestinal parasitic and bacterial pathogens in diarrhoeal and non-diarroeal human stools from Vhembe district, South Africa.

In the present study, a cross-sectional survey of intestinal parasitic and bacterial infections in relation to diarrhoea in Vhembe district and the antimicrobial susceptibility profiles of isolated bacterial pathogens was conducted. Stool samples were collected from 528 patients attending major public hospitals and 295 children attending two public primary schools and were analyzed by standard microbiological and parasitological techniques. Entamoeba histolytica/E. dispar (34.2%) and Cryptosporidium spp. (25.5%) were the most common parasitic causes of diarrhoea among the hospital attendees while Giardia lamblia (12.8%) was the most common cause of diarrhoea among the primary school children (p < 0.05). Schistosoma mansoni (14.4%) was more common in non-diarrhoeal samples at both hospitals (16.9%) and schools (17.6%). Campylobacter spp. (24.9%), Aeromonas spp. (20.8%), and Shigella spp. (8.5%) were the most common bacterial causes of diarrhoea among the hospital attendees while Campylobacter (12.8%) and Aeromonas spp. (12.8%) were most common in diarrhoeal samples from school children. Vibrio spp. was less common (3% in the hospitals) and were all associated with diarrhoea. Antimicrobial resistance was common among the bacterial isolates but ceftriaxone (91%) and ciprofloxacin (88.6%) showed stronger activities against all the organisms. The present study has demonstrated that E. histolytica/dispar, Cryptosporidium, Giardia, and Cyclospora are common parasitic causes of diarrhoea in Vhembe district while Campylobacter spp. and Aeromonas are the most common bacterial causes of diarrhoea in Vhembe district of South Africa.

Entamoeba histolytica: genetic diversity of African strains based on the polymorphism of the serine-rich protein gene.

The polymorphism of the serine-rich Entamoeba histolytica protein (SREHP) among isolates obtained from different geographic regions was analyzed by a nested PCR followed by restriction analysis. Thirteen different profiles were generated from 23 E. histolytica isolates from Cameroon, Zimbabwe and South Africa while 20 others were generated from 38 E. histolytica PCR positive stool samples from South Africa. One of the profiles was common to isolates from Cameroon, Zimbabwe and South Africa and constituted the most prevalent (26.1%) of all the profiles. However, profiles unique to each country were also observed amongst the samples. A non-significant difference was observed between isolates from diarrheic and non-diarrheic samples. Of interest, of the five HIV positive stool samples three had the same profile indicating the possibility that some E. histolytica strains might be more common/pathogenic in immuno-compromised individuals. The results obtained showed that African isolates of E. histolytica may possess extremely complex genetic structures independent of geographic location. This study indicates that certain profiles might be responsible for the presentation of intestinal amoebic symptoms. However, more extended studies need to be performed in order to confirm these observations.

Microsporidiosis in South Africa: PCR detection in stool samples of HIV-positive and HIV-negative individuals and school children in Vhembe district, Limpopo Province.

Microsporidia were initially recognized as pathogens of insects and fish but have recently emerged as an important group of human pathogens, especially in immune-compromised individuals, such as those with HIV infection. In this study, we used a PCR-RFLP assay confirmed by quantitative real-time PCR and trichrome staining to determine the prevalence of microsporidian infections among hospital patients and school children in Vhembe region. Enterocytozoon bieneusi was the only microsporidian species detected in these stool samples. It was found in 33 (12.9%) of 255 samples from the hospitals and in 3 (4.5%) of 67 samples from primary school children and was significantly associated (P=0.039) with diarrhea in HIV-positive patients (21.6%) compared to HIV-negative individuals (9%). However, microsporidian infections were not associated with intestinal inflammation as indicated by the lactoferrin test. These results suggest that microsporidia might be a cause of secretory diarrhea in HIV-positive patients. To our knowledge, this is the first report of E. bieneusi in the Vhembe region of South Africa. Further investigations are needed in order to clarify the pathogenesis of E. bieneusi in HIV-positive patients.

Prevalence of Campylobacter species, Helicobacter pylori and Arcobacter species in stool samples from the Venda region, Limpopo, South Africa: studies using molecular diagnostic methods.

OBJECTIVES: This study determined the prevalence of Campylobacter spp., Helicobacter pylori and Arcobacter spp. in stool samples from Venda in relation to diarrhea, intestinal inflammation and HIV status using specific molecular methods. METHODS: Stool samples were collected from hospital patients (255) and primary school children (67). Genomic DNA was extracted from the stools and molecular methods including PCR, PCR followed by restriction analysis and multiplex PCR were used to test for the different organisms. The lactoferrin content of the stools was determined using commercial kits from TechLab (Blacksburg, VA, USA). RESULTS: The prevalence of the different organisms was 50.6% for H. pylori, 10.2% for C. jejuni, 6.2% for A. butzleri, 6.5% for C. coli, 3.1% for C. concisus, 2.8% for A. cryaerophilus and 1.9% for A. skirrowii. Of all the organisms, only C. jejuni was significantly associated with diarrhea (84.8%) (chi2=21.025, P<0.001) and elevated levels of lactoferrin (78.8%) (chi2=16.919, P<0.005) and was an important pathogen associated with diarrhea among HIV positive individuals (22.8%). CONCLUSIONS: Campylobacter infections are common causes of gastroenteritis in Venda. Non-C. jejuni/coli Campylobacters such as C. concisus as well as A. butzleri and H. pylori may be involved in gastrointestinal diseases in the region but further studies are needed to confirm this hypothesis.

Prevalence, haemolytic and haemagglutination activities and antibiotic susceptibility profiles of Campylobacter spp. isolated from human diarrhoeal stools in Vhembe District, South Africa.

Campylobacter species are increasingly being recognized as agents of gastroenteritis worldwide. However, data on the pathogenic characteristics of the organism isolated in rural communities in South Africa are lacking. In this study, the prevalence of Campylobacter spp. from diarrhoeal stools, haemolytic and haemagglutinating activities of the isolates, and antibiotic susceptibility profiles, including minimum inhibitory concentration (MIC) patterns to different antibiotics, were determined using the standard microbiological techniques. Campylobacter spp. were isolated from individuals of all age-groups; however, the infection rate was higher among individuals aged less than two years (30.4%). Of 115 Campylobacter strains isolated, polymerase chain reaction (PCR) analysis indicated that 98 (85%) were C. jejuni, while 17 (15%) were C. coli. Seventy-one (62%) of the strains showed haemolysis on human blood, and 80% agglutinated human blood, whereas 22.6% were beta-lactamase-positive. Resistance to antimicrobials, such as erythromycin, ciprofloxacin, vancomycin, and fusidic acid, was high. Increased resistance to macrolide and quinolone antibiotics poses major risks for treatment failure. Haemolytic and haemagglutinating activities may be useful in preliminary characterization of pathogenic strains in settings where Campylobacter-associated infections are common.

Prevalence, pathogenesis, antibiotic susceptibility profiles, and in-vitro activity of selected medicinal plants against Aeromonas isolates from stool samples of patients in the Venda region of South Africa.

The prevalence, pathogenic indices, such as haemolytic and haemagglutinating activities, antibiograms, and in-vitro activities of local medicinal plants against Aeromonas isolates in Vhembe district of Limpopo province, South Africa, were studied using standard microbiological methods. In total, 309 diarrhoeic stool samples were collected from patients attending five health centres in the region during December 2004-May 2005. Aeromonas species were identified using the API 20E system. The haemagglutinating and haemolytic activities of isolates on human, sheep, pig and chicken red blood cells were investigated. Antibiotic susceptibility profiles of the isolates to several antibiotics and in-vitro activity of local medicinal plants were also ascertained using previously-reported schemes. Results showed that 104 (33.6%) of the 309 samples were positive for Aeromonas species, of which 89 (85.6%) were Aeromonas hydrophila, 12 (11.5%) A. sobria, and three (2.9%) A. caviae. All strains of A. hydrophila and A. caviae produced haemolysis on sheep blood, while eight of the 12 A. sobria strains were haemolytic on sheep blood. The haemolytic activities of the isolates were variable on other red blood cells tested. High level of resistance was observed to amoxicillin and ampicillin, followed by cefuroxime (79%), chloramphenicol (74%), and erythromycin (65%). The carbapenems were the most active drugs with only 7% resistance to meropenem and 11% to imipenem. About 12% of the isolates were resistant to ciprofloxacin. The extracts of three of seven medicinal plants tested showed inhibitory activity against all Aeromonas isolates; these included acetone and hexane extracts of Pterocarpus angolensis, Syzygium cordatum, and Zornia milneana. The results suggest a high prevalence of Aeromonas species in the region. The isolates demonstrated multiple resistant profiles to different antibiotics tested. Some local medicinal plants were inhibitory to Aeromonas isolates, indicating a potential role in the management of Aeromonas-related infections. Structural elucidation of the active components may pave the way for the discovery of candidate templates for eventual drug design. Most isolates possessed important virulence characteristics based on their haemolytic and haemagglutinating ability. However, the genetic characterization of the isolates will further confirm their pathogenicity and the origin of multiple antibiotic resistance.

Cryptosporidium species: preliminary descriptions of the prevalence and genotype distribution among school children and hospital patients in the Venda region, Limpopo Province, South Africa.

In the present study, the prevalence and species distribution of Cryptosporidium among school children and hospital patients in the Venda region of South Africa was determined. Real time PCR (qPCR) was used for initial screening to detect positive samples while a nested PCR followed by restriction fragment length polymorphism was used to determine the species genotype. From a total of 244 stool samples tested, 44 (18%) had Cryptosporidium with no significant difference (chi(2)=0.04; P=0.841) between samples collected from patients attending hospitals 36/197 (18%) and the samples from primary schools 8/47 (17%). The age groups most affected were those from 2 to 5 years old (28.6%) and 50 to 59 years old (50.0%). Cryptosporidium was detected in 4 (12.5%) of the 31 HIV positive individuals. Fifty-seven percent of the Cryptosporidium positive samples were diarrheic and 26 (59.1%) had elevated lactoferrin content. C. hominis (82%) was more common than C. parvum (18%). This study has demonstrated the high prevalence of Cryptosporidium infections in the Venda region and its implications in causing diarrhea and inflammation.

Effect of exposure to clinic-based health education interventions on behavioural intention to prevent mother-to-child transmission of HIV infection.

HIV and AIDS incidence among infants in South Africa is on the increase. The uptake of prevention of mother-to-child transmission (PMTCT) interventions is often said to be dependent on the beliefs and educational needs of those requiring PMTCT services. This study therefore sought to examine the effect of clinic-based health education interventions (HEI) on behavioural intention of PMTCT among 300 pregnant women from 4 primary health care clinics in Tshilidzini Hospital catchments area, South Africa. An interview schedule was used to obtain information regarding participants' demographic characteristics, level of exposure to clinic-based HEI, salient beliefs and behavioural intention on PMTCT. The major findings included that approximately 85% of the participants had heard of PMTCT. There was very little association between frequency of antenatal clinic (ANC) visits and level of exposure to PMTCT information. Condom use had the lowest set of salient belief scores. Control belief was the most common belief contributing to behavioural intention. Generally, the association between PMTCT salient beliefs and behavioural intention was weak. Clinic-based HEI had an impact on behavioural intention of HIV testing, normative belief of regular ANC visit and nevirapine use. The vital contribution of alternative PMTCT information sources such as the radio and television was observed. Enhancing initiatives that empower women, and a better coordination of the existing HEI through better implementation of health education strategy may strengthen the prevailing moderate PMTCT intention in the area investigated.

Scope of potential bacterial agents of diarrhoea and microbial assessment of quality of river water sources in rural Venda communities in South Africa.

The microbial quality of several, usually untreated, surface domestic water sources, used by rural communities in the Venda Region of South Africa, was assessed to gauge their fitness for human consumption and to highlight the possible impact of waterborne diseases. The water sources studied were six points on the Levubu River and the rivers Mutale, Ngwedi, Tshinane, Makonde, Mutshindudi and Mudaswali. Total and faecal coliform, heterotrophic bacteria, enterococci and coliphage counts were used as indicators/surrogates to estimate the degree of bacterial and viral contamination respectively by standard methods. The presence of potential bacterial agents of diarrhoea such as Salmonella, Shigella, Campylobacter, Plesiomonas, Aeromonas and Vibrio was also determined. Results showed that the ranges of counts with regard to all the water sources investigated were 2.9 x 10(2) - 6.3 x 10(4) CFU/100 mL for faecal coliforms, 6.0 x 10(2) - 3.7 x 10(4) CFU/100 mL for total coliforms, 1.8 x 10(2) - 1.3 x 10(6) CFU/mL for heterotrophic plate count, 1.0 x 10(1) - 3.7 x 10(4) CFU/100 mL for enterococci and 0-13 PFU/100 mL for coliphages. These values are far higher than the acceptable maximum limits prescribed for South Africa by the Dept of Water & Forestry and the Water Research Commission - 0 CFU/100 mL, 5 CFU/100 mL, 1.0 x 10(2) CFU/mL, 0 CFU/100 mL and 1 PFU/100 mL for faecal coliforms, total coliforms, heterotrophic bacteria, enterococci and coliphages respectively. Salmonella, Shigella, Vibrio cholerae, Campylobacter, Aeromonas and Plesiomonas were isolated from several of the water sources investigated. The use of these water sources for drinking and domestic purposes poses a serious threat to the health and well being of the users and calls for urgent government intervention.

Bacteriological examination of milk and milk products sold in Harare.

A study to assess the bacteriological quality of milk and ice cream was conducted using the direct plate count method and the methylene blue dye reduction test. A total of 105 milk and 95 ice cream samples were obtained form two factories (depots) and distributing supermarkets (outlets) in Harare. Under the methylene blue test, all milk and ice cream samples passed the hour and 2 hour tests respectively. However, 99% of the milk and 69% of the ice cream samples reduced the dye after 5.5 and 4 hrs respectively. The results from the direct plate counts revealed the presence of both pathogens and non-pathogens. The median plate counts in the milk and ice cream were found 400 cfu / ml and 100 cfu / ml respectively. Organisms isolated in both samples and in all outlets were similar, these included Bacillus spp. Coagulase Staphlococcus spp., microcuccus spp., Steptococcus spp., Diphthroids, Fusiform bacterial Klebsiella spp., and Citrobacter spp. No significant differences were found in the plate counts of the samples obtained from the depots and outlets for the milk (P = 0.542, df = 1)) and ice cream samples (P = 0.377, df = 1). Results further revealed that there was no significant difference in isolates obtained form strawberry ice cream (0.0096). The study has therefore, revealed that milk and milk product sold in various outlets in Harare contained a variety of bacteria of public health importance and also that the methylene blue dye reduction test is not reliable for the detection of bacterial contaminants in dairy products. It is thus suggested that the use of methylene blue dyes be adapted in combination with other tests such as the plate count in assessing bacterial contaminants in milk products.

In-vitro disk diffusion sensitivity of meropenem against bacterial pathogens in Harare.

OBJECTIVE: To compare the in-vitro sensitivity of meropenem with imipenem and other antibiotics against clinically significant bacteria. DESIGN: A longitudinal survey. SETTING: Department of Medical Microbiology, in a tertiary care university hospital. SUBJECTS: Specimens obtained from patients attending various clinics at tertiary care and teaching hospital in Harare. Those submitted to the Public Health Bacteriology Laboratory were analysed. MAIN OUTCOME MEASURES: Rates of resistance or susceptibility of the various bacteria to the antibiotics employed in the study. RESULTS: There was excellent in-vitro bacterial activity of meropenem against virtually all clinically significant Gram positive and Gram negative isolates when compared with other antibiotics such as imipenem, ciprofloxacin, gentamicin, penicillin, ampicillin, fusidic acid, tetracyclines, erythromycin and clindamycin (p < 0.5). All isolates of Streptococcus pyogenes, Pseudomonas aeruginosa, Enterobacteriaceae, Neisseria meningitidis were susceptible to meropenem. Meropenem showed 99% overall in-vitro sensitivity against Gram positive and Gram negative bacteria. About 80% of staphylococci were resistant to penicillin whereas at least 20-25% of S. aureus, coagulase negative staphylococci, S. pyogenes showed resistance to ampicillin, erythromycin, gentamicin, tetracycline and clindamycin. CONCLUSION: Meropenem is not included in the list of routinely tested antibiotics in our laboratory, a major tertiary laboratory in the country. As a result of the ultra-broad spectrum of activity, we recommend its inclusion in our routine antibiotic sensitivity testing and observe that there is a great potential for meropenem in the treatment of infections caused by several genera of bacteria in our environment.