Histoplasmosis in Africa: a review.

Classical histoplasmosis caused by Histoplasma capsulatum var. capsulatum, and African histoplasmosis caused by H. capsulatum var. duboisii are both endemic in Africa. In South Africa, only classical histoplasmosis caused by Histoplasma capsulatum var. capsulatum is known to occur and cases are seen frequently. It occurs sporadically in several other African countries. Histoplasma capsulatum var. capsulatum is known to occur naturally in caves inhabited by bats in some parts of South Africa, namely, Transvaal and Cape province, Zimbabwe and Tanzania. Outbreaks of histoplasmosis have been reported in cave explorers. Surveys of histoplasmin skin sensitivity carried out in Africa have shown the rate of positive reactors to be from 0.0% to 28%. African histoplasmosis caused by H. capsulatum var. duboisii is prevalent in Western and Central Africa, and in the island of Madagascar between the Kalahari and Sahara deserts, that is between latitudes 20 degrees North and 20 degrees South of the Equator. A natural reservoir of this fungus in soil admixed with bat guano has been found in a bat cave in a rural area, viz. Ogbunike in Anambra State of Nigeria. The clinical features and epidemiology of the two forms of the disease in Africa are reviewed.

Some emerging food and water borne pathogens.

Emerging pathogens are those infective organisms whose incidence has recently increased or is likely to increase during the next two decades due to changes in demography, food habits, food technology, commerce, water sources and environmental factors. Some important emerging food and water borne bacterial pathogens include Listeria monocytogenes, Campylobacter jejuni, Yersinia enterocolitica, Salmonella enteritidis, Escherichia coli O157: H7, Vibrio cholerae biotype E1 Tor Serotype 0139, Vibrio parahaemolyticus and Aeromonas hydrophila, A. sobria, and A. caviae. The prevalence, ecological relationships of these organisms, their transmission through food, water and other environmental sources, and role of their virulent factors in the pathogenesis of infections and their public health significance is discussed in this paper with special reference to the situation in India.

Antibiotic sensitivity of isolates of Pseudomonas aeruginosa in Buraidah, Saudi Arabia.

A study was carried out to determine the pattern of in vitro antibiotic sensitivity of a cross section of the isolates of Pseudomonas aeruginosa recovered from diverse clinical sources during a one year period. One hundred and eighty-six isolates were investigated by disc diffusion method employing multidiscs. Majority of the isolates were sensitive to amikacin (89.7%), tobramycin (75.81%), norfloxacin (68.48%), piperacillin (68.25%), and ceftazidime (58.81%). Other antibiotics were effective for a lesser number of isolates. A few isolates were simultaneously resistant to several antibiotics, viz. gentamicin, carbenicillin, tobramycin, ceftazidime and augmentin. The significance of the findings is discussed.

Microbiological studies on cases diagnosed as typhoid/enteric fever in south-east Nigeria.

Eight hundred and nine patients suspected of having typhoid/enteric fever were investigated. Enteric fever bacilli (Salmonella typhi and S. paratyphi) were cultured from stool samples of 128 (16%) patients. Serological evidence of typhoid fever was obtained in 83 (13%) of 620 of the patients examined by the Widal test. The antibody titres ranged from 1:160 to 1:1280. A higher proportion of paratyphoid infection over typhoid infection was recorded both by culture (56%) and by the Widal test (63%). The predominant serotype was paratyphi C. Non-typhoid Salmonellae were recovered from stool samples of 60 patients, comprising five serovars, namely, S. typhimurium-22 strains, S. enteritidis-15, S. hardar-9, S. virchow-5, S. bredeney-3, and 6 non-typable strains. Shigella sonnei and S. flexneri were detected in diarrhoeic and semi-formed stools of 19 (2.3%) of the typhoid suspects. It is clear from the results of the study that though typhoid is endemic in South-East Nigeria and the number of cases may rise at certain periods of the year, the news of a current wave of epidemic of typhoid seem unfounded.

Nasal carriage of Staphylococcus aureus in hospital staff and its antibiotic sensitivity in Enugu, Nigeria.

The nasal carriage of Staphylococcus aureus was investigated in 475 hospital staff of different categories. The overall carriage was 34.42 per cent with a significantly higher rate in females (67.53 per cent) than in males (23.81 per cent). Nurses, orderlies and attending physicians had a higher carriage rate than other categories of staff investigated. The rate was higher in personnel working in accident, neonatal and postnatal wards than in other wards. As many as 51.94 per cent of the strains of S. aureus were resistant to penicillin while 22.72 per cent of them were resistant to ampicillin.

Reactivity of Cryptococcus neoformans & Candida species with concanavalin A & blood grouping sera.

Forty strains of Cryptococcus neoformans, 30 of Candida albicans, 24 of C. parapsilosis and 10 strains each of C. tropicalis and C. (Torulopsis) glabrata were examined. A 0.2 per cent solution of concanavalin A (Con A) in phosphate buffered saline and commercial anti-A and anti-B blood grouping sera were used in the whole cell slide agglutination test. All the isolates of Candida species strongly reacted with Con A and over 90 per cent were agglutinated by anti-A and -B blood grouping sera. In contrast, except for one strain, Cryptococcus neoformans did not agglutinate with Con A or blood grouping sera. These findings suggest, on one hand, a fundamental difference in the sugar mosaic of the cell surface components of Cryptococcus neoformans and Candida species, and on the other, presence of similar antigenic determinant(s)/receptors on the cell surface of Candida species and human erythrocytes.

Nasal carriage of Naegleria fowleri and its environmental occurrence in Borno State, Nigeria.

The presence of free living amoebae was investigated in the nasal passages of 50 healthy children and in environmental sources in Maiduguri, Borno State of Nigeria. Three of the children yielded positive cultures of Naegleria fowleri. All the five water samples and two of the nine soil samples examined from different localities were positive for N. fowleri. The isolates proved pathogenic for laboratory mice causing a fatal meningoencephalitis. The epidemiological significance of the findings is discussed.

Nasopharyngeal, vaginal and anal carriage of Neisseria meningitidis in Nigeria.

The incidence of carriers of Neisseria meningitidis was investigated in Borno State, an epidemic area for cerebrospinal meningitis and in Anambra State a non-epidemic area for this disease in Nigeria. The nasopharyngeal carriage rate in Maiduguri in Borno State was 18 per cent as compared with 11.8 per cent and 9.6 per cent in Nsukka and Enugu respectively in Anambra State. N. meningitidis was also isolated from anus and vagina in one and three females respectively. Majority of the isolates (71.9 per cent) belonged to serogroup B. The rare group x was recorded on two occasions. Majority of the isolates were sensitive to tetracycline, streptomycin and chloramphenicol; a few multiple drug resistant strains were also encountered.