[Show abstract][Hide abstract] ABSTRACT: Background: In this study, the presence of intestinal parasites in a population group is indicative of lack of proper sanitation, low economic standards and poor educational background.
Aim: To determine the prevalence of intestinal parasites in primary school children of Mthatha,
South Africa and relate this to their socio-economic status. Subjects and Methods: The study population was randomly selected from four governmental schools, rural and urban, from April 2009 to September 2009. A total of 162 learners (85 boys and 77 girls) participated in this survey. Parasitological data were collected by analyzing stool samples using Formalin ethyl-acetate concentration technique. Socio-economic and epidemiologic data were collected by means of a pre-structured questionnaire, covering the important relevant aspects. Results: Out of 162 learners analyzed, 64.8% (105/162) stool samples were positive for ova and cysts of which 57.4% (93/162) were known pathogenic parasites. The most common parasite was Ascaris lumbricoides 29.0% (47/162), followed by Giardia lamblia 9.9% (16/162) and Entamoeba histolytica/dispar 6.8% (11/162) (Other parasites observed but at lower rates of occurrence were Iodamoeba butschlii, Trichuris trichiura, Hymenolepis nana, Taenia spp, Chilomastix mesnili, and Fasciola spp. Our findings showed no significant difference in parasitic infections between urban and rural learners, gender and the age of these learners. Significant associations between parasitic infections and parents’ unemployment and lower education were observed.
Conclusion: Prevalence of worm infestation was more than 50%; therefore, there was a need for mass de-worming of school children in these communities and also a need for other public health interventions like health education programs and improvement of sanitation.
Keywords: Children, Intestinal parasites, Parasite infection, Prevalence
[Show abstract][Hide abstract] ABSTRACT: The presence of intestinal parasites in a population group is indicative of lack of proper sanitation, low economic standards and poor educational background.
To determine the prevalence of intestinal parasites in primary school children of Mthatha, South Africa and relate this to their socio-economic status.
The study population was randomly selected from four governmental schools, rural and urban, from April 2009 to September 2009. A total of 162 learners (85 boys and 77 girls) participated in this survey. Parasitological data were collected by analyzing stool samples using Formalin ethyl-acetate concentration technique. Socio-economic and epidemiologic data were collected by means of a pre-tested structured questionnaire, covering the important relevant aspects, in this descriptive, cross sectional and analytical study. Data were analyzed descriptively and inferentially with SPSS satistical software, and P values of <0.05 were considered as significant.
Out of 162 learners analyzed, 64.8% (105/162) stool samples were positive for ova and cysts of which 57.4% (93/162) were known pathogenic parasites. The most common parasite was Ascaris lumbricoides 29.0% (47/162), followed by Giardia lamblia 9.9% (16/162) and Entamoeba histolytica/dispar 6.8% (11/162) (Other parasites observed but at lower rates of occurrence were Iodamoeba butschlii, Trichuris trichiura, Hymenolepis nana, Taenia spp, Chilomastix mesnili, and Fasciola spp. Our findings showed no significant difference in parasitic infections between urban and rural learners, gender and the age of these learners. Significant associations between parasitic infections and parents' unemployment and lower education were observed.
Prevalence of worm infestation was more than 50%; therefore, there was a need for mass de-worming of school children in these communities and also a need for other public health interventions like health education programs and improvement of sanitation.
[Show abstract][Hide abstract] ABSTRACT: Background
The increasing problem of multi-drug-resistant (MDR) tuberculosis (TB) [ie resistant to at least isoniazid (INH) and rifampicin (RIF)] is becoming a global problem. Successful treatment outcome for MDR-TB depends on reliable and accurate drug susceptibility testing of first-line and second-line anti-TB drugs.
Consecutive M. tuberculosis isolates identified as MDR-TB during August 2007 to January 2008 using the BACTEC MGIT 960 systems and the agar proportion method were included in this study. Susceptibility testing of MDR-TB isolates against ethambutol (EMB) and streptomycin (STR) as well as two second-line anti-TB drugs, kanamycin (KAN) and ofloxacin (OFX) was performed using the BACTEC MGIT 960 systems at a routine diagnostic laboratory. The results were compared to those obtained by the agar proportion method.
The agreement between the BACTEC MGIT 960 system and the agar proportion method was 44% for EMB, 61% for STR and 89% for both KAN and OFX. The sensitivity and specificity of the BACTEC MGIT 960 system using the agar proportion method as a gold standard was 92% and 37% for EMB, 95% and 37% for STR, 27% and 97% for KAN and 84% and 90% for OFX, respectively.
The BACTEC MGIT 960 system showed acceptable sensitivity for EMB, STR, and OFX; however, the BACTEC MGIT 960 system was less specific for EMB and STR and demonstrated a low sensitivity for KAN. The lower agreement found between the two methods suggests the unreliability of the BACTEC MGIT 960 system for the drugs tested. The reasons for the lower agreement between the two methods need to be investigated and further studies are needed in this setting to confirm the study finding.
Full-text · Article · Dec 2012 · BMC Infectious Diseases
[Show abstract][Hide abstract] ABSTRACT: Despite South Africa being one of the high-burden multidrug-resistant tuberculosis (MDR-TB) countries, information regarding the population structure of drug-resistant Mycobacterium tuberculosis strains is limited from many regions of South Africa. This study investigated the population structure and transmission patterns of drug-resistant M. tuberculosis isolates in a high-burden setting of South Africa as well as the possible association of genotypes with drug resistance and demographic characteristics. A total of 336 consecutive MDR-TB isolates from four provinces of South Africa were genotyped using spoligotyping and mycobacterial interspersed repetitive-unit-variable number tandem repeat (MIRU-VNTR) typing. Drug susceptibility testing for ofloxacin, kanamycin, and capreomycin was performed using the agar proportion method. The results showed that 4.8% of MDR-TB isolates were resistant to ofloxacin, 2.7% were resistant to kanamycin, and 4.5% were resistant to capreomycin, while 7.1% were extensively drug resistant (XDR), and the remaining 83.6% were susceptible to all of the second-line drugs tested. Spoligotyping grouped 90.8% of the isolates into 25 clusters, while 9.2% isolates were unclustered. Ninety-one percent of the 336 isolates were assigned to 21 previously described shared types, with the Beijing family being the predominant genotype in the North-West and Limpopo Provinces, while the EAI1_SOM family was the predominant genotype in the Gauteng and Mpumalanga Provinces. No association was found between genotypes and specific drug resistance patterns or demographic information. The high level of diversity and the geographical distribution of the drug-resistant M. tuberculosis isolates in this study suggest that the transmission of TB in the study settings is not caused by the clonal spread of a specific M. tuberculosis strain.
Full-text · Article · May 2012 · Journal of clinical microbiology
[Show abstract][Hide abstract] ABSTRACT: The presence of multi-drug resistant Acinetobacter baumannii raises a big therapeutic challenge in our hospital. Tigecycline, a new glycylcycline with expanded broad spectrum of activity against multi-drug resistant organisms was recently licensed in South Africa.
The aim of this study was to evaluate the in vitro activity of tigecycline against carbapenem resistant A. baumannii complex.
Consecutive clinical isolates of carbapenem resistant A. baumannii complex were collected between February and July 2010. Species identification and susceptibility testing was performed by Vitek-2 colorimetric compact system with Advanced Expert System (AES). Strains were tested for carbapenemase production by the modified Hodge test, according to the Clinical and Laboratory Standards Institute (CLSI) guidelines.
A total of 232 carbapenem resistant clinical isolates of A. baumannii complex were collected over the six months study period; 217 (93.5%) of these were modified Hodge test positive. All isolates were susceptible to colistin and 174 (78%) susceptible to amikacin whilst 20 (9%) were susceptible to ciprofloxacin. For tigecycline 169 (75.8%) were fully susceptible, 37 (16.6%) intermediately resistant and only 17 (7.6%) were fully resistant. None of the carbapenem resistant isolates were susceptible to ampicillin, amoxicillin/clavullanic acid, piperacillin/tazobactam, cefuroxime, cefuroxime axetil, cefoxitin, cefepime or nitrofurantoin.
All carbapenem resistant isolates were found to be fully susceptible to colistin; amikacin and tigecycline susceptibility was 78% and 76% respectively. Treatment options for infections due to carbapenem and multi-drug resistant A. baumannii organisms are limited and hence tigecycline and amikacin may be considered. The properties of tigecycline i.e. stability, safety, low toxicity, non cross-resistance with other antibiotics and its efficacy against multi-drug resistant A. baumannii isolates make it a good choice. However, ongoing monitoring of A. baumannii susceptibility to tigecycline is needed.
Full-text · Article · May 2012 · BMC Research Notes
[Show abstract][Hide abstract] ABSTRACT: Objective: The treatment of serious Salmonella infections which requires the use of cephalosporins and fluoroquinolones is being compromised by the emergence of extended-spectrum beta-lactamases (ESBLs). This study reports the antibiotic profile of Salmonella species, highlighting increasing ESBLs trends in Salmonella spp. and the emergence of multi-drug resistance (MDR). To proffer solution to the problem of MDR, screening of selected herbal plants was carried out.
Methods: 142 consecutive isolates of Salmonella spp. collected over a period of 4 years were tested for antibiotic resistance. Antibiogram, ESBL phenotype and confirmation of isolate were determined using a semi-automated antibiotic test. Tests were performed based on Clinical Laboratory Standards Institute standards for broth microdilution methods and interpretation using Escherichia coli ATCC 25922 as the control strain. Antibiotic resistant patterns were determined, ranking order of importance as percent (%) of each type of resistance. Twelve plants selected based on ethnobotanical survey information as remedy in the treatment of stomach related ailments were screened using broth microdilution methods against strains of Salmonella and Shigella, Escerichia, Staphylococcus, Psedomonas and Enterococcus.
Results: A greater proportion of isolates were obtained from invasive cultures. Of the Salmonella isolates, there was a striking predominance of S. enterica serotype Typhi followed by S. enteric serotype Typhimurium. Most species showed pentavalent resistance to commonly used drugs. Antimicrobial resistance in S. enteric serotype Typhi is visibly increasing. Of growing concern is the increase in strains exhibiting ESBLs. Plant screening revealed promising therapeutic values in Aloe arborescens, A. Striatula, and Psidium guajava.
Conclusion: Increasing MDR in Salmonella serovars involved ESBLs’ production.
Plants with significant antibacterial activities were comparable to the tested antibiotic giving credence to their use in ethnomedicine. With further isolation of bioactive components, these plants may be a relief to multidrug resistance enteric pathogens.
[Show abstract][Hide abstract] ABSTRACT: The GenoType® MTBDRsl assay is a new rapid assay for the detection of resistance to second-line anti-tuberculosis drugs.
To evaluate the MTBDRsl assay on 342 multidrug-resistant tuberculosis isolates for resistance to ofloxacin (OFX), kanamycin (KM), capreomycin (CPM) and ethambutol (EMB), to compare the results to the agar proportion method, and to test discrepant results using DNA sequencing.
The sensitivity and specificity of the MTBDRsl assay were respectively 70.3% and 97.7% for OFX, 25.0% and 98.7% for KM, 21.2% and 98.7% for CPM and 56.3% and 56.0% for EMB. DNA sequencing identified mutations that were not detected by the MTBDRsl assay. The 8/11 phenotypically OFX-resistant isolates had mutations in gyrA (2/8 had an additional mutation in the gyrB gene), 1/11 had mutations only in the gyrB gene, 6/21 phenotypically KM-resistant isolates had mutations in the rrs gene, and 7/26 and 20/26 phenotypically CPM-resistant isolates had mutations in the rrs and tlyA genes.
The MTBDRsl assay showed lower sensitivity than previous studies. The assay performed favourably for OFX; however, it was less sensitive in the detection of KM/CPM resistance and demonstrated low sensitivity and specificity for EMB resistance. It is recommended that the MTBDRsl assay include additional genes to achieve better sensitivity for all the drugs tested.
Full-text · Article · Jan 2012 · The International Journal of Tuberculosis and Lung Disease
[Show abstract][Hide abstract] ABSTRACT: Representative gels for PCR amplification of DNA extracted from selected E. coli isolates showing the presence of diverse virulence genes. A: 100 bp molecular weight marker (lanes 1 and 10), fragment from aggR (lanes 2 to 4), eaeA (lanes 5 to 6) and astA (lanes 7 to 9). B: 100 bp molecular weight marker (lanes 1 and 6), fragment from aggR (lanes 2 to 3), virA (lanes 4) and LT (lanes 5). The relative positions in the gel of predicted size of PCR products are indicated by arrowheads on the right sides.
[Show abstract][Hide abstract] ABSTRACT: Apart from localized gastrointestinal infections, Escherichia coli and Salmonella species are major causes of systemic disease in both humans and animals. Salmonella spp. cause invasive infections such as enteric fever, septicemia, osteomyelitis and meningitis while certain types of E. coli can cause systemic infections, includingpyelonephritis, meningitis and septicemia. These characteristic requires the involvement of a myriad of virulence factors.
This study investigated the virulence factors of Escherichia coli and Salmonella species in clinical specimens from patients with diarrhoea presenting to health care centres in Oliver R. Tambo District Municipality, Eastern Cape Province, Republic of South Africa. Microbiology analysis involved the use of cultural and molecular techniques.
Out of a total of 315 samples screened, Salmonella isolates were obtained in 119 (37.8%) of cases and these comprised: S. choleraesuis (6%), S. enteritidis (4%), S. eppendorf (1%), S. hadar (1%), S. isangi (8%), S. panama (1%), S. typhi (52%), S. typhimurium (25%) and untyped Salmonella spp. (2%). Among the Salmonella species 87 (73.1%) were invasive. Using molecular diagnostic methods, diarrheagenic E. coli were detected in 90 cases (28.6%): the greater proportion of this were enteroaggregative E. coli (EAEC) 37 (41.1%), enteropathogenic E. coli (EPEC) 21 (23.3%) and enterohemorrhagic E. coli (EHEC) 21 (23.3%). The predominant virulence gene among the diarrheagenic E. coli was EAEC heat-stable enterotoxin astA genes while the virulence genes identified in the Salmonella strains were 15 (12.6%) flic and 105 (88.2%) inv genes. The amino acid identity of the representative genes showed 95-100% similarity to corresponding blast searched sequence.
This study showed the diversity of virulence gene expression in two major enteric pathogens. S. typhi and enteroaggregative E. coli were the predominant enteropathogens in our study area with an indication that EAEC is endemic within our study population. It was observed among other things that some diarrheagenic E. coli isolated from apparently asymptomatic subjects expressed some virulence genes at frequency as high as seen in diarrheagenic cases. This study underlines the importance of understanding the virulence composition and diversity of pathogens for enhanced clinico-epidemiological monitoring and health care delivery.
[Show abstract][Hide abstract] ABSTRACT: Representative gels for PCR amplification of DNA extracted from selected Salmonella isolates showing the presence of diverse virulence genes. 100 bp molecular weight marker (lanes 1 and 8) fliC (lanes 2 to 4) and invA (lanes 5 to 7). The relative positions in the gel of predicted size of PCR products are indicated by arrowheads on the right sides. The relative positions in the gel of predicted size of PCR products are indicated by arrowheads on the right sides.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate the diagnostic potential of immunocytochemistry against the Bacille Calmette-Guérin (BCG) antigen on pleural fluid for the diagnosis of pleural tuberculosis. Immunocytochemistry refers to the process of localizing proteins in cells and exploiting the principle of antigens binding to their respective antibodies. Visualization is enabled by tagging the antibody with color producing tags. Consecutive pleural fluid specimens were cytospun and stained for the BCG antigen. Specimens were cultured on Lowenstein Jensen media. After incubation, culture slopes were washed with distilled water and washings used to perform real-time Polymerase Chain Reaction (PCR) assay for mycobacteria. Immunocytochemistry detected mycobacteria in 10/102 (9.8%) specimens compared to 22/102 (21.6%) by culture and 26/102 (25.5%) by real-time PCR. This gave a sensitivity of 27% [95%CI: 16, 34] and specificity of 96% [95%CI: 92, 99] (p = 0.002). Immunocytochemistry detecting the BCG antigen was not useful for the diagnosis of pleural tuberculosis.
No preview · Article · Jan 2011 · Current Research in Tuberculosis
[Show abstract][Hide abstract] ABSTRACT: In settings of high human immunodeficiency virus (HIV) prevalence, culture confirmation, preferably by liquid culture, is required for the diagnosis of tuberculosis (TB). However, long delays with phenotypic identification offsets the short turnaround time of liquid cultures. We report here the advantages of using a commercial immunochromatographic (ICT) assay targeting the Mycobacterium tuberculosis protein 64 (MPT-64) Ag and compare it with the Accuprobe MTB complex molecular probe assay. The performance of the ICT kit was excellent, with sensitivity, specificity, positive and negative predictive values of respectively 97%, 100%, 100%, and 92%. The kit requires a 15-min assay time, is easy to perform and is a good method for simplifying the diagnosis of TB.
No preview · Article · Sep 2009 · The International Journal of Tuberculosis and Lung Disease
[Show abstract][Hide abstract] ABSTRACT: The aim of the study was to evaluate the diagnostic potential of immunohistochemistry using an antibody to the secreted mycobacterial antigen MPT64, specific for Mycobacterium tuberculosis complex organisms, on formalin-fixed biopsies from patients with pleural tuberculosis (TB) from a high TB and HIV endemic area.
Pleural biopsies from 25 TB cases and 11 non-TB cases were studied. Ziehl-Neelsen staining for acid-fast bacilli and immunohistochemistry with anti-MPT64 and anti-Bacille Calmette-Guérin (BCG) antibodies was performed. Nested polymerase chain reaction (N-PCR) for IS6110 was performed for comparison. Acid-fast bacilli were detected in only 2 cases and 3 biopsies showed granulomas with caseous necrosis. Immunostaining with anti-MPT64, anti-BCG, and N-PCR were positive in 20 (80%), 12 (48%), and 16 (64%) of the cases, and 0, 3 (27%), and 2 (18%) of the non-TB controls, respectively. The diagnostic validity of immunohistochemistry was calculated by comparison with N-PCR-positive TB cases and N-PCR-negative non-TB controls. The sensitivity of immunohistochemistry with anti-MPT64 and anti-BCG were 81% and 56% respectively, and the corresponding specificities were 100% and 78%.
Detection of the MPT64 antigen by immunohistochemistry improves the diagnosis of TB pleuritis caused by M. tuberculosis complex organisms in patients living in HIV-endemic areas with atypical histology and negative staining for acid-fast bacilli.
Full-text · Article · Sep 2008 · Applied immunohistochemistry & molecular morphology: AIMM / official publication of the Society for Applied Immunohistochemistry
[Show abstract][Hide abstract] ABSTRACT: The aim of the study was to improve the diagnosis of pleural tuberculosis (TB) based on formalin-fixed biopsies from patients living in high TB and human immunodeficiency virus (HIV) endemic areas. A real-time polymerase chain reaction (real-time PCR) assay targeting a segment of the gene for mycobacterial 65-kd heat shock protein was developed and evaluated on pleural biopsies from 25 patients clinically diagnosed as having TB, on the basis of the good response to treatment, and from 11 controls. A nested polymerase chain reaction (N-PCR) assay for the repetitive genetic sequence insert IS6110, common to Mycobacterium tuberculosis complex organisms, was performed for comparison. When compared with N-PCR, the real-time PCR assay gave a sensitivity and specificity of 83% and 72%, respectively. When compared with clinical diagnosis, the sensitivity and specificity of real-time PCR (68% and 73%, respectively) was comparable with the sensitivity and specificity of the N-PCR assay (64% and 82%, respectively). There were no major differences in the diagnostic validity for the confirmed TB/HIV coinfected patients compared with the results from the whole TB group. In conclusion, the overall accuracy of the real-time PCR assay was comparable with that of the N-PCR and both were equally useful as diagnostic tools in the setting of a HIV coinfection. The real-time PCR has the additional advantage of a short turn-around time, low risk of sample contamination, and offers the possibility to quantify bacterial load, making it a powerful tool for the rapid diagnosis of TB pleuritis.
Full-text · Article · Jul 2008 · Diagnostic molecular pathology: the American journal of surgical pathology, part B
[Show abstract][Hide abstract] ABSTRACT: Diagnosis of tuberculous (TB) pleuritis is difficult and better diagnostic tools are needed. New blood based interferon-gamma (IFN-γ) tests are promising, but sensitivity could be low in HIV positive patients. The IFN-γ tests have not yet been validated for use in pleural fluid, a compartment with higher level of immune activation than in blood.
The QuantiFERON TB®-Gold (QFT-TB) test was analysed in blood and pleural fluid from 34 patients presenting with clinically suspected pleural TB. Clinical data, HIV status and CD4 cell counts were recorded. Adenosine deaminase activity (ADA) analysis and TB culture were performed on pleural fluid.
The patients were categorised as 'confirmed TB' (n = 12), 'probable TB' (n = 16) and 'non-TB' pleuritis (n = 6) based on TB culture results and clinical and biochemical criteria. The majority of the TB patients were HIV infected (82%). The QFT-TB in pleural fluid was positive in 27% and 56% of the 'confirmed TB' and 'probable TB' cases, respectively, whereas the corresponding sensitivities in blood were 58% and 83%. Indeterminate results in blood (25%) were caused by low phytohemagglutinin (PHA = positive control) IFN-γ responses, significantly lower in the TB patients as compared to the 'non-TB' cases (p = 0.02). Blood PHA responses correlated with CD4 cell count (r = 0.600, p = 0.028). In contrast, in pleural fluid indeterminate results (52%) were caused by high Nil (negative control) IFN-γ responses in both TB groups. Still, the Nil IFN-γ responses were lower than the TB antigen responses (p < 0.01), offering a conclusive test for half of the patients. We did not find any correlation between blood CD4 cell count and IFN-γ responses in pleural fluid.
The QFT-TB test in blood could contribute to the diagnosis of TB pleuritis in the HIV positive population. Still, the number of inconclusive results is too high to recommend the commercial QFT-TB test for routine use in pleural fluid in a TB/HIV endemic resource-limited setting.
Full-text · Article · Mar 2008 · BMC Infectious Diseases
[Show abstract][Hide abstract] ABSTRACT: Adenosine Deaminase Activity (ADA) is a commonly used marker for the diagnosis of tuberculous pleural effusion. There has been concern about its usefulness in immunocompromised patients, especially HIV positive patients with very low CD4 counts. The objective of this study was to evaluate the sensitivity of ADA in pleural fluid in patients with low CD4 counts.
This was a retrospective case control study. Medical files of patients with tuberculous pleuritis and non-tuberculous pleuritis were reviewed. Clinical characteristics, CD4 cell counts in blood and biochemical markers in pleural fluid, including ADA were recorded.
One ninety seven tuberculous pleuritis and 40 non-tuberculous pleuritis patients were evaluated. Using the cut-off value of 30 U/L, the overall sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of ADA was 94%, 95%, 19, and 0.06 respectively. The mean CD4 cell counts among TB pleuritis patients was 29 and 153 cells/microL in patients with CD4 <50 cells/microL and >50 cells/microL, (p<0.05) respectively. The corresponding mean ADA values for these patients were 76 U/L and 72 U/L respectively (p>0.5). There was no correlation between ADA values and CD4 cell counts (r = -0.120, p = 0.369).
ADA analysis is a sensitive marker of tuberculous pleuritis even in HIV patients with very low CD4 counts in a high TB endemic region. The ADA assay is inexpensive, rapid, and simple to perform and is of great value for the immediate diagnosis of tuberculous pleuritis while waiting for culture result and this has a positive impact on patient outcome.