Antifungal activity of essential oils from Cymbopogon: inter- and intraspecific differences.

The influence of the genetic background of Cymbopogon species on the antifungal activity of essential oils derived from the plants was investigated against three yeast-like and nine filamentous fungi. Essential oils from distinct strains of the aromatic grass Cymbopogon showed interspecific and intraspecific differences in antifungal activity.

Efficacy of an unsupervised ambulatory treatment regimen for smear-negative pulmonary tuberculosis and tuberculous pleural effusion in Malawi.

SETTING: Queen Elizabeth Central Hospital, Blantyre, and Zomba Central Hospital, Zomba, Malawi. OBJECTIVE: To evaluate treatment outcome of unsupervised ambulatory treatment (2R3H3Z3/2TH[EH]/4H) in Blantyre and 'standard' treatment (1STH[SEH]/11TH[EH]) in Zomba in human immunodeficiency virus (HIV) seropositive and seronegative patients with smear-negative pulmonary tuberculosis (PTB) and pleural TB. DESIGN: All patients with smear-negative and pleural TB registered between 1 April and 31 December 1995 were assessed for enrolment in the study. Study patients were followed up and 12-month treatment outcomes were recorded. RESULTS: A total of 434 patients, 296 with smear-negative PTB and 138 with pleural TB, were enrolled: 366 (84%) of patients were HIV-positive; 220 (51%) completed treatment, and 144 (33%) died by 12 months. In patients from Blantyre and Zomba, baseline characteristics were similar, apart from older age in those from Zomba, and the proportion of patients who completed treatment and who died were similar. In both sites, significantly higher case fatality rates were found in older patients, HIV-positive patients and patients with pulmonary parenchymal lung disease. CONCLUSION: Unsupervised ambulatory treatment evaluated in this study had an efficacy similar to that of 'standard' treatment. For operational reasons, however, it will not be recommended for widespread use in Malawi's National Tuberculosis Control Programme.

Management of pulmonary tuberculosis suspects with negative sputum smears and normal or minimally abnormal chest radiographs in resource-poor settings.

SETTING: Queen Elizabeth Central Hospital, Blantyre, Malawi. OBJECTIVES: 1) To determine the proportion of pulmonary tuberculosis (PTB) suspects with negative sputum smears and a normal/minimally abnormal chest radiograph (CXR) who are culture-positive for Mycobacterium tuberculosis, and 2) to determine how many develop smear or radiographic evidence of PTB (TB CXR) during follow-up. METHODS: PTB suspects with negative sputum smears and a normal/minimally abnormal CXR were given a second course of antibiotics and followed up at 3-week intervals over 3 months with repeat sputum smears and chest radiography. RESULTS: Of 79 patients (38 men and 41 women, mean age 33 years) with negative smears and a normal/minimally abnormal CXR, 16 (21%) were culture-positive for M. tuberculosis. Of 15 culture-positive patients who were alive and attended follow-up, seven (47%) developed a TB-CXR by 3 months. Of 41 culture-negative patients who were alive and attended follow-up, 13 (32%) developed a TB-CXR, including one patient who became sputum smear-positive. TB-CXRs were found only in patients with a cough. CONCLUSION: TB suspects with negative smears and normal/minimally abnormal CXRs in high human immunodeficiency virus (HIV) prevalent countries should be given a second course of antibiotics. If cough improves, patients can be advised not to return for further follow-up. If cough continues, patients should return for further follow-up with sputum smear examination and chest radiography. Approximately 50% of those who have culture-positive PTB will develop a TB-CXR by 3 months and can be identified if radiographic facilities are available.

Prevalence of tuberculosis in TB suspects with short duration of cough.

The prevalence of pulmonary tuberculosis (PTB) in patients with short duration of cough was determined. Ninety-eight adult out-patients (60 men, 38 women; mean age 32 years) at Queen Elizabeth Central Hospital, Blantyre, Malawi, who had cough for 1-3 weeks which was unresponsive to a course of antibiotics, were successfully screened by microscopy and culture of 2 or 3 sputum specimens and chest radiography; 34 (35%) had PTB. Ten patients were sputum smear-positive and 24 were smear-negative and culture-positive. There was no difference in age, gender or clinical features of general illness, respiratory disease and HIV-related disease between patients with PTB and those with no evidence of PTB. Nine patients (26%) with microbiologically confirmed tuberculosis (TB) had chest radiograph abnormalities consistent with TB, compared with 5 (8%) of patients with no microbiological evidence of TB. Certain classes of patients with a short history of cough would benefit from PTB screening strategies with the emphasis on sputum examination rather than chest radiography, which is unreliable in such patients. The classes include (i) patients with other features of TB whose cough has not improved with antibiotic therapy, (ii) seriously ill patients, and (iii) patients in high risk institutions such as prisons and refugee camps.

Screening pulmonary tuberculosis suspects in Malawi: testing different strategies.

Alternative strategies for screening tuberculosis (TB) suspects are needed in sub-saharan Africa. Ambulatory adult TB suspects who were seen in the chronic cough room of Queen Elizabeth Central Hospital, Blantyre, Malawi, were assessed with respect to appropriateness of referral. Appropriate referrals (patients with cough 3 weeks or longer, weight loss and no antibiotic response) were screened by 3 sputum specimens for microscopy and culture of Mycobacterium tuberculosis and chest radiography (CXR). Hypothetical strategy A (screening by sputum smear examination followed by CXR in patients with negative sputum smears) was compared with strategy B (screening by CXR followed by sputum smear examination in patients with a CXR consistent with TB) in terms of diagnostic efficacy and cost. Of 1127 patients referred to the cough room, 402 (38%) were appropriate TB suspect referrals. Of these, 111 (28%) were sputum smear-positive, 213 (53%) were culture-positive, and 221 (55%) had smear and/or culture-positive evidence of TB. Routine CXR was consistent with pulmonary (P) TB in 230 patients (57%). With strategy A, 243 (60%) patients were diagnosed as PTB, but 40 (25%) of those not diagnosed as PTB had positive mycobacterial cultures. With strategy B, 230 patients (57%) were diagnosed as PTB, but 53 (31%) of those not diagnosed as PTB had positive mycobacterial cultures, including 13 with smear-positive sputum. The cost per diagnosed case of PTB was US$ 4.63 with strategy A and US$ 5.44 with strategy B. Screening patients with good criteria of TB has high diagnostic sensitivity, but screening by CXR is less effective and more costly than screening by sputum smear microscopy.

Cryptococcal meningitis in African children.

Three cases of cryptococcal meningitis in Malawian children aged 6 weeks, 3 years and 9 years are described. Only 23 cases of cryptococcal meningitis in children have been described previously, but in children from Europe and the USA. These are therefore the first cases of cryptococcosis to be described in African children.

PIP: The majority of cryptococcal meningitis cases in sub-Saharan Africa occur in adults infected with HIV. Reported in this paper are the first 3 cases of cryptococcal meningitis to involve African children. All 23 such cases reported to date in the literature have involved children from the US and Europe. The 3 African children--ages 6 weeks, 3 years, and 9 years--were from Malawi. Definitive evidence of HIV infection existed in the 9-year-old child, and the mother of the 6-week-old infant was HIV-seropositive. The mother of the 3-year-old child refused authorization of HIV serodiagnosis. None of the children had clinical signs of AIDS. The episode of cryptococcal meningitis was most likely the first AIDS-defining illness for these children. The 9-year-old child died 6 days after hospital admission.

Tuberculous lymphadenitis, a diagnostic problem in areas of high prevalence of HIV and tuberculosis.

The human immunodeficiency virus (HIV) epidemic is associated with a marked increase of tuberculosis cases. The influence of HIV on diagnostic methods for tuberculous lymphadenitis is less clear. In an environment of high HIV and tuberculosis prevalence in Blantyre, Malawi, a prospective study compared results of basic procedures diagnosing tuberculous lymphadenitis with the outcome of histology and/or culture. One hundred out-patients, aged 15-55 years, with extra-inguinal lymphadenopathy not responding to general antibiotics, entered the study. Among 52 cases, with whom all procedures were carried out in accordance with the protocol, 38 (73%) were diagnosed as tuberculous lymphadenitis; 84% of the latter (32/38) were seropositive for HIV. Needle aspirate and biopsy smears stained by the Ziehl-Neelsen technique contributed little to detecting tuberculosis, 8% and 11% respectively. In contrast, macroscopic caseation of excised lymph nodes showed a high yield of 82%, which was similar to histology, and higher than that of Löwenstein-Jensen culture (61%). The study suggested that HIV positivity of tuberculous lymphadenitis patients decreased the possibility of histology and culture both being indicative of tuberculosis (odds ratio 0.10; P = 0.06). Consequently histology results, often used as the single definitive method, failed to diagnose 18% (7/38) of tuberculosis cases. However, it was reassuring that 4 simple methods, which can safely be carried out at district level, could be expected to diagnose 80-95% of tuberculous lymphadenitis cases in a timely and cost-effective manner.

PIP: A prospective study conducted in 1994-95 in Blantyre, Malawi, investigated the influence of HIV on diagnostic methods for tuberculous lymphadenitis in 100 outpatients 15-55 years old with extra-inguinal lymphadenopathy not responsive to general antibiotics. For the 52 cases for which all diagnostic procedures were carried out, 38 (73%) were diagnosed as tuberculous lymphadenitis; 32 (84%) of these patients were HIV-positive. Needle aspirate and biopsy smears stained by the Ziehl-Neelsen technique contributed only 8% and 11%, respectively, to detecting tuberculosis. In contrast, macroscopic caseation of excised lymph nodes, histology, and Lowenstein-Jensen culture had yields of 82%, 82%, and 61%, respectively. These findings indicate that, in tuberculous lymphadenitis patients, HIV infection decreases the diagnostic power of culture and histology. However, use of the other methods can diagnose 80-95% of tuberculous lymphadenitis cases in a cost-effective manner in areas with high prevalences of both HIV and tuberculosis.

Antibacterial and antifungal activity of aromatic constituents of essential oils.

Five aromatic constituents of essential oils (cineole, citral, geraniol, linalool and menthol) were tested for antimicrobial activity against eighteen bacteria (including Gram-positive cocci and rods, and Gram-negative rods) and twelve fungi (three yeast-like and nine filamentous). In terms of antibacterial activity linalool was the most effective and inhibited seventeen bacteria, followed by cineole, geraniol (each of which inhibited sixteen bacteria), menthol and citral aromatic compounds, which inhibited fifteen and fourteen bacteria, respectively. Against fungi the citral and geraniol oils were the most effective (inhibiting all twelve fungi), followed by linalool (inhibiting ten fungi), cineole and menthol (each of which inhibited seven fungi) compounds.

Carriage of penicillin-resistant pneumococci in Malawian children.

In a prospective study of pneumococcal carriage in 200 Malawian children under 5 years of age, 47.5% were carriers. The carriage rate was highest in those aged 3-12 months and did not vary with family size, nor was it higher in those who had recently been admitted to hospital. Nasopharyngeal swabs were significantly more efficient than throat swabs in detecting carriers (p < 0.001) but nasopharyngeal swabs alone would have missed seven (8%) carriers. Pneumococcal isolates from 22% of carriers and from eight cases of meningitis and one of empyema showed intermediate resistance to penicillin (MIC 0.1-1.0 mg/l). All were sensitive to the 3rd-generation cephalosporin cefotaxime but one of the penicillin-resistant pneumococci and two of the clinical isolates had increased MICs of cefuroxime (0.5 mg/l).

Chloramphenicol-resistant bacterial meningitis in Malawi.

Three recent cases of chloramphenicol-resistant pyogenic meningitis are reported from Malawi. The implications of the emergence of antibiotic-resistant strains of Streptococcus pneumoniae and Haemophilus influenzae type b causing childhood meningitis are discussed.

Antibacterial and antifungal activity of ten essential oils in vitro.

The essential oils of aegle, ageratum, citronella, eucalyptus, geranium, lemongrass, orange, palmarosa, patchouli and peppermint, were tested for antibacterial activity against 22 bacteria, including Gram-positive cocci and rods and Gram-negative rods, and twelve fungi (3 yeast-like and 9 filamentous) by the disc diffusion method. Lemongrass, eucalyptus, peppermint and orange oils were effective against all the 22 bacterial strains. Aegle and palmarosa oils inhibited 21 bacteria; patchouli and ageratum oils inhibited 20 bacteria and citronella and geranium oils were inhibitory to 15 and 12 bacterial strains, respectively. All twelve fungi were inhibited by seven oils (aegle, citronella, geranium, lemongrass, orange, palmarosa and patchouli). Eucalyptus and peppermint oils were effective against eleven fungi. Ageratum oil was inhibitory to only four fungi tested. The MIC of eucalyptus, lemongrass, palmarosa and peppermint oils ranged from 0.16 to > 20 microliters ml-1 for eighteen bacteria and from 0.25 to 10 microliters ml-1 for twelve fungi.

Characterization of resistance to essential oils in a strain of Pseudomonas aeruginosa (VR-6).

VR-6, a strain of Pseudomonas aeruginosa, harboured a plasmid and was not inhibited by 20 microliters ml-1 of essential oils (eucalyptus, lemongrass, palmarosa, and peppermint). On treatment with acridine orange, a clone VR-6-AO-1 was obtained which was susceptible to 16.6 microliters ml-1 of eucalyptus or palmarosa oil. The plasmid DNA content of this clone was similar to the parent strain.

Antibacterial activity of essential oils from Cymbopogon: inter- and intra-specific differences.

The influence of the genetic background of a plant on the antibacterial activity of essential oil derived from it was investigated. Essential oils from six distinct strains of Cymbopogon were tested against eighteen bacteria. Interspecific and intra-specific differences were evident in the antibacterial activity of the essential oils derived from the the six Cymbopogon strains.

Effect of essential oils on the viability and morphology of Escherichia coli (SP-11).

The four essential oils (aromatic plant products) from palmarosa (Pm), lemongrass (Lg), peppermint (Pt) and eucalyptus (Eu) plants were found to be bactericidal to Escherichia coli strain SP-11, at a concentration of 1.66 (Pm, Lg and Eu) or 2.5 (Pt) microl ml-1. This effect was observed both at 37 degrees C and 4 degrees C and was not prevented by immediate tenfold dilution or by the presence of 0.5 M sucrose. Pm and Pt but not Lg or Eu induced the formation of elongated filamentous forms, some measuring 60-70 micrometers long.

Subcutaneous infection due to Curvularia species.

A Curvularia species was isolated from a chronic ulcer on the lower limb of a 21-year-old man. The histopathological findings supported the mycological diagnosis. An enzyme-linked immunosorbent assay (ELISA) was performed using a crude soluble fungal antigen. The patient's serum contained significantly more antibodies than 10 sera from control subjects (P < 0.05, t-test).

Filariasis and malaria sera from Orissa (India) lack human immunodeficiency virus (HIV) antibody reactivity.

Reports exist indicating a correlation between seropositivity for human T-lymphotrophic virus (HTLV) antibodies and certain parasitic infections in some parts of the world. In 274 filariasis and 119 malarla sera examined from Orissa, none was reactive in a test for antibodies to human immunodeficiency virus (HIV).

Antibodies to microfilarial sheath in bancroftian filariasis--prevalence and characterization.

Antibodies directed towards the sheaths of microfilariae have been implicated in the elimination of circulating microfilariae, both in experimental and human filariasis. In the present study antisheath antibodies have been detected in human sera by indirect immunoperoxidase assay (IPA) using fixed Wuchereria bancrofti microfilariae as antigen. One hundred and eighteen sera collected from an area endemic for Bancroftian filariasis were tested. While 80% of sera from microfilariae carriers had no demonstrable antisheath antibodies, more than 80% of amicrofilaraemic samples (chronic filariasis cases and endemic normals) had antisheath antibodies. The antibody activity was found in IgG, IgM and also IgE isotypes. IgG subclass typing with monospecific antisera revealed significantly higher antisheath activity in IgG2 in comparison with other IgG subclasses. The determinants on sheathed microfilariae reacting with antisheath antibodies were found to be thermostable (100 degrees C for 30 minutes), resistant to protease treatment and significantly sensitive to sodium periodate treatment, indicating the possible role of carbohydrate moieties in eliciting protective antisheath antibodies in Bancroftian filariasis.

Filariasis and malaria sera from Orissa lack HTLV-III antibody reactivity.

Reports exist indicating a correlation between seropositivity for human T-lymphotrophic virus (HTLV) antibodies and certain parasitic infections in some parts of the world. In 274 filariasis and 119 malaria sera examined from Orissa, none was reactive in a test for anti-HTLV-III antibodies.