Yacoob Coovadia

Yacoob Coovadia
National Health Laboratory Service · Department of Medical Microbiology

MBcHB , FF Path[microbiology ]

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94
Publications
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Publications

Publications (94)
Article
Purpose: The present study was done to evaluate the antimycobacterial activity of aqueous and methanol extracts of nine plants viz., Buddleja saligna, Carpobrotus dimidiatus, Capparis tomentosa, Dichrostachys cinerea, Ekebergia capensis, Ficus sur, Gunnera perpensa, Leonotis leonurus and Tetradenia riparia in South Africa. Methods: Aqueous and meth...
Article
Introduction: The prevalence of azole resistance in C. parapsilosis is very low in most parts of the world. However, South Africa has reported an exceptionally high prevalence of azole resistance in C. parapsilosis strains isolated from candidaemia cases. We aimed to determine the possible molecular mechanisms of fluconazole resistance in C. parap...
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Background: Hospital acquired infections are on the increase worldwide. A possible source for transmission is the presence of microorganisms on mobile phones which are carried by increasing numbers of medical and nursing staff, students, and caregivers. Methods: A cross-sectional study was performed. Samples were obtained from medical and nursing...
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Neonatal candidaemia is a common, deadly and costly hospital-associated disease. To determine the genetic diversity of Candida parapsilosis causing fungaemia in South African neonatal intensive care units (NICUs). From February 2009 through to August 2010, cases of candidaemia were reported through laboratory-based surveillance. C. parapsilosis iso...
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Buddleja saligna (family Buddlejaceae) is a medicinal plant endemic to South Africa. Two isomeric pentacyclic triterpenes, oleanolic acid and ursolic acid, were isolated from the leaves of B. saligna using silica gel column chromatography. Compounds oleanolic acid and ursolic acid were subjected to derivatization with acetic anhydride in the presen...
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From February 2009 through August 2010, we compared species-level identification of bloodstream Candida isolates and susceptibility to fluconazole, voriconazole, and caspofungin between diagnostic and reference South African laboratories during national surveillance for candidemia. Diagnostic laboratories identified isolates to genus/species level...
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Background: Hospital acquired infections are on the increase worldwide. A possible source for transmission is the presence of microorganisms on mobile phones which are carried by increasing numbers of medical and nursing staff, students, and caregivers. Methods: A cross-sectional study was performed. Samples were obtained from medical and nursing s...
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Objectives: To compare Candida species distribution and antifungal susceptibility at South African public- and private-sector hospitals. Methods: From February 2009 through to August 2010, laboratory-based surveillance for candidaemia was undertaken at 11 public-sector hospitals and >85 private-sector hospitals across South Africa. A case was de...
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Capreomycin is a key antimycobacterial drug in treatment of extensively drug-resistant tuberculosis (XDR-TB). Drug susceptibility testing (DST) for capreomycin is not routinely performed in newly diagnosed XDR-TB in South Africa. We performed this study to assess the prevalence, clinical significance, and molecular epidemiology of capreomycin resis...
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Non-tuberculous mycobacteria (NTM) are important environmental pathogens capable of causing a spectrum of infection. The different species exhibit varied geographical prevalence worldwide. Identification of the infecting organism may be helpful in determining the clinical significance of the isolate. To describe the spectrum of NTM isolated from cl...
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We determined the susceptibility of 102 clinical isolates C. neoformans from Durban, South Africa to amphotericin B, fluconazole, flucytosine and voriconazole using broth microdilution according to the Clinical & Laboratory Standards Institute M27-A3 document and compared these results with Etest and Vitek 2®. Essential agreement (EA) of Etest and...
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Setting: The dual epidemics of HIV-TB including MDR-TB are major contributors to high morbidity and mortality rates in South Africa. Rifampicin (RIF) resistance is regarded as a proxy for MDR-TB. Currently available molecular assays have the advantage of rapidly detecting resistant strains of MTB, but the GeneXpert does not detect isoniazid (INH)...
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Background: Tuberculous meningitis (TBM) is difficult to diagnose promptly. The utility of the Xpert MTB/RIF test for the diagnosis of TBM remains unclear, and the effect of host- and sample-related factors on test performance is unknown. This study sought to evaluate the sensitivity and specificity of Xpert MTB/RIF for the diagnosis of TBM. Meth...
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Objective: HIV-infected patients with treated cryptococcal meningitis are at risk for further neurological deterioration after commencing combination antiretroviral therapy (cART), mostly because of cryptococcosis-associated immune reconstitution inflammatory syndrome (C-IRIS). Identifying predictors of C-IRIS could enable risk stratification. De...
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Neisseria meningitidis is a leading cause of pyogenic meningitis worldwide, as well as causing large epidemics in parts of Africa. With the dramatic decline in cases of Haemophilus influenzae B, N. meningitidis has emerged as one of the most common causes of acute bacterial meningitis in children and adults in South Africa. However, it remains an u...
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A series of 2‐(substituted phenyl/benzyl‐amino)‐6‐(4‐chlorophenyl)‐5‐(methoxycarbonyl)‐4‐methyl‐3,6‐dihydropyrimidin‐1‐ium chlorides 7–13 and 15 was synthesized in their hydrochloride salt form. The title compounds were characterized by FT‐IR, NMR (1H and 13C) and elemental analysis. They were evaluated for their in vitro antitubercular activity ag...
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Background: Anaesthetic equipment is a potential vector for the transmission of disease. This study was undertaken to observe current infection control practices among anaesthetic nurses regarding the decontamination of anaesthetic equipment in regional, tertiary and central hospitals in KwaZulu-Natal.Method: All hospitals that were classified as r...
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Objectives: Contaminated anaesthetic equipment has been implicated in the nosocomial transmission of infection. The aim of this study was to determine the prevalence of blood (occult or visible) and/or visible organic material contamination of anaesthetic equipment deemed to be ready for use in theatres in regional, tertiary and central hospitals i...
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Objectives: Unsafe injection and vial usage practices, including the reuse of needles and syringes for different patients, is one of the leading causes of the iatrogenic spread of blood-borne diseases. A study was conducted to determine the prevalence of the reuse of single-patient syringes and spinal fentanyl ampoules among anaesthetists at region...
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We evaluated some of the regimens recommended for the antimicrobial prophylaxis of infective endocarditis prior to dental extraction in 160 patients. Group A patients served as the control group, group B subjects rinsed their mouths with chlorhexidene, group C subjects took 3 g amoxicillin orally and group D patients took 600 mg clindamycin orally....
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We conducted a study to determine the frequency of bacteraemias following dental extraction and common oral procedures, namely tooth brushing and chewing, and the relationship between bacteraemia and oral health in black patients. Positive blood cultures were detected in 29.6% of patients after dental extraction, in 10.8% of patients after tooth br...
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A series of polycyclic 'cage' derivatives of N-geranyl-1,2 diamines were synthesized and screened for their anti-mycobacterial activity against H(37)Rv, multidrug resistant (MDR) and extensively drug-resistant (XDR) strains of tuberculosis. By substituting the adamantyl skeleton of SQ109 with trishomocubanyl (9), oxa-pentacycloundecyl (14, 16), pen...
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The antimicrobial activity of five novel SQ109 derivatives including SQ109 against bacteria, yeast and filamentous fungi is reported herein. Using broth microdilution techniques, compounds 2 and 3 were found to be active against most tested fungi and bacteria, with minimum inhibitory concentrations (MICs) ranging from 0.98 to 31 μg ml−1, except for...
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Depsidomycin is a cyclic heptadepsi-peptide isolated from the cultured broth of Streptomyces lavendofoliae MI951-62F2. It exhibits significant antimicrobial and immunosuppressive activity. The total synthesis of a depsidomycin analogue in which 1,2-piperazine-3-carboxylic acid was substituted with proline is described. After several trials using di...
Article
The antifungal and antimicrobial activities of three pentacycloundecane (PCU) tetra-amine derivatives are reported herein. The in vitro activity of these PCU derivatives against yeasts (Candida albicans and non-albicans species) and filamentous fungi was evaluated using the Clinical and Laboratory Standards Institute (CLSI) M27-A2 and M38-A2 guidel...
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Salmonella enterica serotype Enteritidis is a universally recognized cause of foodborne disease. In South Africa, outbreaks of foodborne disease are generally under reported. We investigated the etiology of acute gastroenteritis in 216 patients who presented to a rural hospital in KwaZulu-Natal, South Africa, after consuming a meal at a school func...
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The yield of mycobacterial blood cultures for multidrug-resistant (MDR) and extensively drug-resistant tuberculosis (XDR-TB) among drug-resistant TB suspects has not been described. We performed a retrospective, cross-sectional analysis to determine the yield of mycobacterial blood cultures for MDR-TB and XDR-TB among patients suspected of drug-res...
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Current tools for the rapid diagnosis of tuberculous meningitis (TBM) are suboptimal. We evaluated the clinical utility of a quantitative RD-1 IFN-gamma T-cell enzyme-linked immunospot (ELISPOT) assay (T-SPOT.TB), using cerebrospinal fluid cells for the rapid immunodiagnosis of TBM. To evaluate the diagnostic utility of the RD1 antigen- specific EL...
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The yield from aspirating lymph nodes and pleural fluid for diagnosing extensively drug-resistant (XDR) tuberculosis is unknown. Mycobacterium tuberculosis was cultured from lymph node or pleural fluid aspirates of 21 patients; 7 (33%) cultures grew XDR M. tuberculosis. Additive diagnostic yield for XDR M. tuberculosis was found in parallel culture...
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Streptococcus agalactiae is a well-established cause of neonatal meningitis, whereas Acinetobacter baumannii, often seen as a contaminant, has only rarely been reported to cause meningitis without a neurosurgical predisposition. We report of a case of neonatal meningitis in a preterm neonate in which both S. agalactiae and A. baumannii were conside...
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Community-acquired acute bacterial meningitis is a life-threatening infection and many outbreaks have been reported all around the world. We analysed 330 cerebrospinal fluid (CSF) samples received over a period of eight months from patients older than one month. Microscopy, cultures, identification, and antigen detection were performed for the posi...
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The advent of HIV and AIDS has brought about many diagnostic and management challenges regarding multiple J opportunistic infections. Pneumocystis jirovecii pneumonia (PCP) is a common presentation in patients with AIDS who are not on prophylaxis or highly active antiretroviral therapy (HAART). Herpes simplex 1 virus (HSV-1) is a ubiquitous virus t...
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In the last week of May 2005, staff at Mahatma Gandhi Memorial Hospital in KwaZulu-Natal realised that many babies in the high-care nursery ward had bloodstream infections involving Klebsiella pneumoniae bacteria. Attempts to identify a common source of infection failed. The ward was therefore closed and new babies needing high care were admitted t...
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The response of male gonococcal urethritis to a single 250 mg dose of ciprofloxacin versus 500 mg was studied. Both regimens were given in combination with doxycycline in the context of the local syndromic management protocol. There was no significant difference in response between the regimens, inclusive/exclusive of tetracycline susceptible isola...
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To create a prognostic model for complications of blood culture-proven typhoid fever in adults (> or = 15 y old), a retrospective cohort was assembled though review of the medical records of the hospitalized patients treated for typhoid fever over a 3-y period ending January 1995. Of the 59 patients included, 21 (35.6%) developed various complicati...
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Clinical features, laboratory findings, and complications of typhoid fever were correlated with sex through a retrospective case note review of 102 hospitalized culture-positive patients in Durban, South Africa. Intestinal perforation (P = 0.04), occult blood losses in stools (P = 0.04), and a mild reticulocytosis in the absence of hemolysis (P = 0...
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A retrospective case note review was undertaken to assess the clinical significance of hepatic dysfunction with jaundice in typhoid fever. Of the 57 patients, 21 (36.8%) had jaundice, while 36 (63.2%) did not have jaundice. Significantly higher proportions of jaundiced patients were females (P = 0.04). Confusion (P = 0.01), upper abdominal pain (P...
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Four cases of typhoid fever complicated by both acute oliguric renal failure and hepatitis are presented. Two patients had type II hepatitis according to criteria proposed by Khosla et al. (30) with hepatomegaly, hyperbilirubinaemia and markedly elevated asparate transaminase (AST); the others had type III hepatitis, characterized clinically and bi...
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In an attempt to evaluate various clinical and laboratory features available within 24 h of admission, prior to the Widal test and bacteriological culture results as potential diagnostic aids in typhoid fever, we undertook a retrospective unit-based case control study in 90 febrile adult and paediatric patients admitted to King Edward VIII Hospital...
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We report on a case of dual infection with Cryptococcus neoformans and Streptococcus pneumoniae in the cerebrospinal fluid of a patient with AIDS. To our knowledge this represents the first case to be reported in the English literature. In immunocompromised patients the importance of performing both the Gram- and India-ink stain and cryptococcal an...
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Ten patients with asymptomatic human immunodeficiency virus (HIV) infection were treated for typhoid fever at King Edward VIII Hospital, Durban, South Africa, from 1993 through 1995. The mean age was 23.7 years (range, 8-33 years), with a female-to-male ratio of 9 to 1 and mortality and morbidity rates of 20% and 10%, respectively. Common presentin...
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We retrospectively compared the clinical manifestations, laboratory features, and outcome of cryptococcal meningitis in 44 human immunodeficiency virus (HIV)-positive and 21 HIV-negative patients in Durban, South Africa, and contrasted our findings with those in the developed world. Cryptococcal meningitis was the initial AIDS-defining illness in 8...
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The clinical and microbiological data of 60 neonates, 23 from the Neonatal Unit (Group I) and 37 (Group II) from the General Paediatric Wards with meningitis are presented. The overall prevalence/1000 was significantly lower in Group I (0.36) than in Group II (1.11; P < 0.0001). This low incidence follows the introduction of amikacin for the treatm...
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The gamma interferon (gamma-IFN) concentration and the adenosine deaminase (ADA) activity were evaluated in 30 patients with tuberculous peritonitis, 21 patients with ascites due to a malignant disorder, and 41 patients with cirrhosis. The gamma-IFN concentrations were significantly higher (p < 0.0001) in tuberculous peritonitis patients (mean: 6.7...
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A case of disseminated strongyloidiasis in an Indian diabetic patient who was not receiving any immunosuppressive therapy, is reported. Strongyloides stercoralis was detected in peritoneal fluid, stools and blood. To our knowledge this represents the first such case to be reported in the English literature. The need for both clinicians and microbio...
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During a 3-week period, nine babies in the neonatal unit of a large teaching hospital in Durban were infected or colonized with Klebsiella pneumoniae resistant to a range of antimicrobial agents including amikacin and cefotaxime. Resistance to cefotaxime was reduced by clavulanic acid in vitro suggesting production of extended-spectrum beta-lactama...
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Nine cases, 3 adults and 6 children, with Listeria monocytogenes meningitis were seen over a 10-year period at King Edward VIII Hospital, Durban. These cases accounted for 0.8% (3/374) and 0.6% (6/1,210) of all culture-positive cases of acute bacterial meningitis in adults and children, respectively, and represented 2.9% (4/136) of all culture-posi...
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Typhoid fever caused by Salmonella typhi remains endemic to many parts of South Africa, including Natal and KwaZulu, Northern Transvaal and the Transkei. Until recently, the majority of S. typhi isolates from South Africa have remained susceptible to ampicillin/amoxycillin and chloramphenicol, and only three cases of typhoid due to multi-antibiotic...
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Leucopenia with neutropenia and a relative lymphocytosis are believed to be common findings in patients with typhoid fever. This paper reviews 191 adult patients with typhoid. The total and differential leucocyte counts done on admission were analysed. In this study leucopenia was found in only 24.6% of patients. Whilst complications occurred at an...
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In this, the first report of group B streptococcal (GBS) infections in Asian neonates in South Africa, the incidence was 2.65/1000 live births over a period of 3.5 years. Early onset disease (EOD), defined as arising less than or equal to 5 days after birth, was present in 79% cases; in most of these, the onset was before the age of 24 h. One baby...
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A study of wound colonization by bacteria in 49 consecutive admissions was conducted over a 2-month period in patients with burns at King Edward VIII and Clairwood Hospitals, Durban, neither of which possess proper burn units. Specimens for culture were collected from patients, staff and the environment. Bacteria most frequently isolated were Staph...
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A case of typhoid fever caused by a multiply antibiotic resistant strain of Salmonella typhi is reported. The S. typhi strain was resistant to ampicillin, chloramphenicol and sulphamethoxazole-trimethoprim. Treatment with cefotaxime, resulted in a clinical and bacteriological cure, but the infection relapsed within a month after completion of thera...
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The features of typhoid fever in Indian South Africans are described. In children the illness was usually uncomplicated. However, anaemia, thrombocytopenia and hypo-albuminaemia were found in both adults and children. The initial symptoms on presentation of diarrhoea and vomiting frequently led to a misdiagnosis of gastro-enteritis. The previous ad...
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All cases of bacterial meningitis in the neonatal unit at King Edward VIII Hospital, Durban for the period 1 January 1981 to 31 December 1987 were reviewed. In particular, we looked at the impact of cefotaxime on mortality rates and amikacin on the incidence of hospital-acquired Gram-negative bacillary (GNB) meningitis. Klebsiella was found to be t...
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A community-based study was undertaken to compare the organisms responsible for diarrhoea in children living in formal housing with indoor water supply and sanitation with those from a deprived environment. The role of "home remedies" was also assessed. Among 373 children with diarrhoea, rotavirus was detected in 15% (in 371 symptom-free controls,...
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The routine laboratory monitoring of methicillin-resistant strains of Staphylococcus aureus (MRSA) at a large teaching hospital led to the detection of a new, multiply-resistant strain of MRSA, which was resistant not only to penicillin, oxacillin, methicillin, cephamandole, erythromycin, tetracycline, kanamycin and gentamicin but also to rifampici...
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An enzyme-linked immunosorbent assay (ELISA) was designed to detect the inhibition of BCG-anti-BCG reactions by soluble antigens of Mycobacterium tuberculosis. Eighty-four samples were tested of which 59 were of cerebrospinal fluid (CSF) (25 control, 10 bacterial, 14 viral and 10 tuberculous meningitis); and twenty-five were of pleural or ascitic f...
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Using two different inoculum sizes (10(4) and 10(7) organisms), we tested 35 penicillinase-producing (PPNG) and 72 non-PPNG strains of Neisseria gonorrhoeae falling into three categories (penicillin-sensitive, intermediately resistant, and resistant) by the agar-dilution method against 15 beta-lactam antibiotics. With the exception of penicillin, a...
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Anti-lipopolysaccharide equine hyperimmune plasma (anti-LPS), which has been used successfully to treat LPS (endotoxin)-mediated disorders, has been further characterised. IgG present in anti-LPS had the highest affinity for LPS prepared from Salmonella typhimurium, S. typhi, S. abortus equi and Shigella flexneri and intermediate affinity for Esche...
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A rare case of purulent meningitis caused by vancomycin-resistant Leuconostoc sp. is reported. The patient was treated successfully with penicillin G, and there were no neurological sequelae. We recommend that all gram-positive cocci isolated from cerebrospinal fluid and blood be fully identified so as not to confuse Leuconostoc spp. with more comm...
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A cryptococcal latex agglutination test (Crypto-La; International Biological Laboratories, Canbury, New Jersey, USA) was evaluated for its ability to detect cryptococcal antigen in cerebrospinal fluid (CSF) specimens obtained from black patients with a clinical diagnosis of meningitis. Of the 445 Gram-stained and bacterial culture-negative CSF spec...
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Three commercially available latex agglutination tests and the Gram stain were evaluated for their ability to detect Haemophilus influenzae, Streptococcus pneumoniae and Neisseria meningitidis in cerebrospinal fluid (CSF) specimens from 160 patients suspected of having meningitis. Bactigen detected 86% of all culture-positive CSF specimens, whereas...
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A retrospective survey was undertaken to determine the incidence of chloramphenicol-resistant Salmonella typhi in Durban, South Africa. Of the 3313 strains tested over a 7 year period 20 (0.6%) showed intermediate resistance to chloramphenicol and 19 (0.6%) were fully resistant. Resistance to chloramphenicol was found to fluctuate over the period s...
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A passive haemagglutination test, using sheep red blood cells sensitised with Salmonella typhi lipopolysaccharide, was compared with the Widal test for the serological diagnosis of typhoid fever in an endemic area. The results obtained on sera from 152 patients with bacteriologically confirmed typhoid and 183 patients who did not have typhoid were...