Streptococcus agalactiae (group B streptococcus (GBS)) colonisation and persistence, in pregnancy; a comparison of two diverse communities (rural and urban).

OBJECTIVE: To establish the extent of GBS colonisation, persistence of colonisation in pregnancy and influence of obstetric history in two diverse communities (rural and urban) in Zimbabwe. DESIGN: Cross sectional survey. SETTING: Rutsanana Clinic in Highfield, Harare (representing the urban area) and Chitsungo Mission Hospital in Lower Guruve, (representing the rural area). SUBJECTS: 300 and 100 pregnant women from the urban and rural areas respectively. MAIN OUTCOME MEASURES: GBS colonisation and persistence rates for both urban and rural areas were established, together with pregnancy outcome. RESULTS: Mother colonisation rate was significantly higher in the rural areas (60%) as compared to the urban areas (46%). GBS colonisation persistence was evidently more in rural (48%) that in urban women (12%). Baby colonisation was also more in the rural (23%) that in urban area (5%). In both the rural and urban areas, flu-like illness was a common feature and was equally reported by the subjects. Vaginal discharge requiring treatment, previous stillbirths and previous miscarriages were equally reported in both communities.

Use of culture methods for recovery of atypical mycobacteria from stools of AIDS patients.

OBJECTIVE: To establish recovery rates of atypical mycobateria from stools of suspected AIDS patients using culture media. DESIGN: Laboratory evaluation of recovery rates, contamination rates, optimum exposure time and optimum concentration of alkali used for decontamination. SETTING: The study was conducted in Harare, Zimbabwe at two medical institutions: Beatrice Road Infectious Diseases Hospital (BRIDH) (a tuberculosis referral hospital) and Mashambanzou Care Unit (MCU) (a home-based care centre). SUBJECTS: A total of 386 stool specimens from suspected AIDS patients from the two health institutions plus 81 stool specimens from clinically healthy patients were collected. The number of patients from MCU was 144 (49 females, 95 males) and 242 from BRIDH (119 males, 123 females). MAIN OUTCOME MEASURE: The main goals were to determine optimum exposure time and optimum concentration of alkali used in decontamination and to identify the culture medium with the best recovery rates of atypical mycobacteria. RESULTS: Optimum recovery of atypical mycobacteria was achieved on Peizer TB medium after treating stool specimens with 4% sodium hydroxide for 35 minutes. In addition, the use of Kirchner's medium improved isolation rates, although with a slight increase in contamination at levels of 2.9%. CONCLUSION: A stool specimen can be used to recover atypical mycobacteria in suspected AIDS patients. Recovery is achieved using Peizer TB medium at a concentration of 4%. Varying the exposure time of the stool specimen to the decontaminating alkali and incorporating antifungal agents and antibiotics into the medium, improves recovery of atypical mycobacteria.

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.

In-vitro activity of piperacillin and tazobactam combination against clinically significant bacteria.

The in-vitro activity of piperacillin/tazobactum which is not among the routinely tested antibiotic at the Public Health Bacteriology Laboratory, Parirenyatwa Hospital, Harare, Zimbabwe was evaluated for its activity against bacterial pathogens using the Kirby-Bauer disk diffusion method. Piperacillin/tazobactum showed superior in-vitro activity against both gram positive and gram negative bacteria when compared with routinely tested antibiotics such as gentamicin, erythromycin, tetracycline, penicillin, chloramphenicol, fusidic acid and clindamycin and the difference was statistically significant (p < 0.05). Ciprofloxacin showed in-vitro activity comparable to that of tazobactam/piperacillin. Specifically, 96% of gram positive isolates (comprising Streptococcus pyogenes, Staphylococcus aureus, coagulase negative staphylococci and Streptococcus pneumoniae were sensitive to piperacillin/tazobactam. For gram negative organisms, 98% of Haemophilus influenzae Shigella spp, Klebsiella spp were also sensitive to the combination. The broad spectrum of activity of piperacillin/tazobactam shows that the potential of the drug combination for the treatment of infections caused by diverse microorganisms should not be underestimated. We recommend its inclusion in routine antibiotic sensitivity testing in our hospital.

Control of intracellular growth of Mycobacterium fortuitum by human monocytes in vitro.

The ability of human monocytes to phagocytize and respond to infection by Mycobacterium fortuitum was tested using the method of Crowle and May. The monocytes were obtained from heparinized donor blood samples and separated from lymphocytes by adherence to plastic surfaces. M. fortuitum infection was performed immediately. Intracellular viability was indicated by colony forming units (CFU) done at 2 hour intervals. Monocytes were found to cause a rapid reduction in CFU during the first 2 hours of incubation. The rate of killing of M. fortuitum decreased thereafter but continued for the entire 8-hour study period. In parallel tests, ciprofloxacin and ofloxacin were added to the culture medium. Increased intracellular killing was observed with drug concentrations above 2 x MIC in both cases. Ofloxacin showed better antimycobacterial effects than ciprofloxacin.

Pulmonary diseases in patients infected with the human immunodeficiency virus in Zimbabwe, Central Africa.

During the 11 month period up to 30 September 1987, 37 patients (26 male, 11 female, mean age 27 years) with respiratory symptoms who were human immunodeficiency virus (HIV) positive, were studied prospectively on 40 occasions to determine the cause of any pulmonary complications. HIV was heterosexually transmitted. Predominant symptoms were cough (89%), fever (89%), weight loss (83%), and dyspnoea (60%). Transnasal fibre-optic bronchoscopy (with bronchoalveolar lavage, bronchial brushings and transbronchial lung biopsies) was performed on 35 patients, twice on 3 patients. 'Tru-cut' lung biopsies were obtained from 2 patients who died before bronchoscopy. Pulmonary tuberculosis was the commonest disease, being found in one-third of the patients (12 of 37). Mycobacterium tuberculosis was cultured from 4; the remainder of the plates were contaminated. Pneumocystis carinii was present in 8 patients: as the sole pathogen in 3, with Streptococcus pneumoniae in 4, Staphylococcus aureus in 2, and one also had tuberculous lymphadenitis. Endobronchial Kaposi's sarcoma was seen in 6 of 7 patients with skin nodules. Bacterial pathogens isolated included Staph. aureus (5), S. pneumoniae (5), Klebsiella pneumoniae (2), Haemophilus influenzae (2), H. parainfluenzae (1) and Pseudomonas aeruginosa (1). Invading Aspergillus fumigatus was diagnosed by lung biopsy in one. No diagnosis was reached for 8 patients. It is concluded that in Central Africa pulmonary complications in AIDS patients are similar to those in Europe and North America but the incidence of different pathogens depends on the prevalence of pathogens in the community. M. tuberculosis is probably the commonest pathogen. This study has confirmed that P. carinii pneumonia does occur, but occurs less frequently.

Collagenolytic activity of Coccidioides immitis.

Coccidioides immitis appears to be unable to digest particulate collagen when cultured on collagen-containing semisolid culture media. However, all C. immitis strains solubilized collagen when the fungus was grown in liquid suspension cultures. Moreover, sterile culture filtrates were collagenolytic in collagen-buffer-agar plate assays.

Elastase activity of fungi with anamorphs similar to Coccidioides immitis.

The elastin digestion assay was examined to determine if it would facilitate the identification of Coccidioides immitis when non-pathogenic fungi resembling C. immitis are encountered. Fungal isolants tested have anamorphs that closely resemble the macroscopic or microscopic morphology of C. immitis. Elastin hydrolysis was measured by elastin-agar plate assays. Approximately 80% of the isolants hydrolyzed elastin; thus, the elastin digestion assay as a differential test appears to have little value.

Elastase activity of Coccidioides immitis.

Twenty-two strains of Coccidioides immitis were tested for the ability to hydrolyse elastin. Screening assays with Czapek's or Tryptic Soy Agar supplemented with 0.5% elastin demonstrated that 21 strains (95%) were elastolytic. In broth cultures, elastase activity was induced by incorporation of insoluble elastin into the medium and induction was suppressed by supplementation with yeast extract. C. immitis appears to be unique amongst dimorphic fungal pathogens in its digestion of elastin.