Amoebic liver abscess with negative serologic markers for Entamoeba histolytica: mind the gap!

A 38-year-old male German traveller returning from Asia presented with fever, night sweats and abdominal complaints. Abdominal ultrasonography revealed several fast-growing abscesses of the liver. Three blood cultures as well as serologic investigations for the detection of antibodies to Entamoeba histolytica, performed on day 3 and 7 after the onset of clinical symptoms, remained negative. Stool microscopy revealed the presence of amoeba cysts compatible with E. histolytica infection. Taking both the amoebic and bacterial etiology of the abscesses into consideration, the patient was treated with metronidazole and ciprofloxacin followed by paromomycin. Antibodies to E. histolytica tested positive shortly after anti-amoebic therapy was initiated. The patient fully recovered, and ultrasound follow-up showed complete resolution of the abscesses within 50 days. This case leads to the conclusion that amoebic liver abscess should be considered despite negative amoeba serology and that ultrasonography is an important diagnostic tool for the early diagnosis of extraintestinal amoebiasis.

Mother-to-child transmission of HIV and its prevention: awareness and knowledge in Uganda and Tanzania.

Awareness and knowledge about HIV mother-to-child transmission (MTCT) and preventive measures in different population groups and health personnel were analysed in future intervention areas in western Uganda and southwestern Tanzania. In Uganda, a total of 751 persons (440 clients of antenatal and outpatient clinics, 43 health workers, 239 villagers, 29 traditional birth attendants) and in Tanzania, 574 persons (410 clients, 49 health workers, 93 villagers, 18 traditional birth attendants) were interviewed. When given options, knowledge on transmission during pregnancy and delivery in women was 93% and 67% in Uganda and Tanzania respectively, and 86% and 78% for transmission during breastfeeding. In Uganda 59% of male interviewees did not believe that HIV is transmitted during breastfeeding. Expressed acceptance of HIV testing was above 90% in men and women in both countries, but only 10% of the clients in Uganda and 14% in Tanzania had been tested for HIV infection. Health workers' knowledge regarding MTCT was acceptable, while traditional birth attendants' knowledge on both MTCT and preventive measures was extremely poor. Recom endations on infant feeding were not compatible with WHO recommendations for HIV-infected women. If prevention of MTCT (PMTCT) interventions are to be accepted by the population and promoted by health personnel, thorough orientation and training are mandatory.

Anaerobic oxidation of o-xylene, m-xylene, and homologous alkylbenzenes by new types of sulfate-reducing bacteria.

Various alkylbenzenes were depleted during growth of an anaerobic, sulfate-reducing enrichment culture with crude oil as the only source of organic substrates. From this culture, two new types of mesophilic, rod-shaped sulfate-reducing bacteria, strains oXyS1 and mXyS1, were isolated with o-xylene and m-xylene, respectively, as organic substrates. Sequence analyses of 16S rRNA genes revealed that the isolates affiliated with known completely oxidizing sulfate-reducing bacteria of the delta subclass of the class Proteobacteria. Strain oXyS1 showed the highest similarities to Desulfobacterium cetonicum and Desulfosarcina variabilis (similarity values, 98.4 and 98.7%, respectively). Strain mXyS1 was less closely related to known species, the closest relative being Desulfococcus multivorans (similarity value, 86.9%). Complete mineralization of o-xylene and m-xylene was demonstrated in quantitative growth experiments. Strain oXyS1 was able to utilize toluene, o-ethyltoluene, benzoate, and o-methylbenzoate in addition to o-xylene. Strain mXyS1 oxidized toluene, m-ethyltoluene, m-isoproyltoluene, benzoate, and m-methylbenzoate in addition to m-xylene. Strain oXyS1 did not utilize m-alkyltoluenes, whereas strain mXyS1 did not utilize o-alkyltoluenes. Like the enrichment culture, both isolates grew anaerobically on crude oil with concomitant reduction of sulfate to sulfide.

Anaerobic utilization of alkylbenzenes and n-alkanes from crude oil in an enrichment culture of denitrifying bacteria affiliating with the beta-subclass of Proteobacteria.

Denitrifying bacteria were enriched from freshwater sediment with added nitrate as electron acceptor and crude oil as the only source of organic substrates. The enrichment cultures were used as laboratory model systems for studying the degradative potential of denitrifying bacteria with respect to crude oil constituents, and the phylogenetic affiliation of denitrifiers that are selectively enriched with crude oil. The enrichment culture exhibited two distinct growth phases. During the first phase, bacteria grew homogeneously in the aqueous phase, while various C1-C3 alkylbenzenes, but no alkanes, were utilized from the crude oil. During the second phase, bacteria also grew that formed aggregates, adhered to the crude oil layer and emulsified the oil, while utilization of n-alkanes (C5 to C12) from the crude oil was observed. During growth, several alkylbenzoates accumulated in the aqueous phase, which were presumably formed from alkylbenzenes. Application of a newly designed, fluorescently labelled 16S rRNA-targeted oligonucleotide probe specific for the Azoarcus/Thauera group within the beta-subclass of Proteobacteria revealed that the majority of the enriched denitrifiers affiliated with this phylogenetic group.