Iranian HIV/AIDS patients with oropharyngeal candidiasis: identification, prevalence and antifungal susceptibility of Candida species.

Oropharyngeal candidiasis is the commonest mucocutaneous infection in HIV-positive individuals. Herein, samples were taken from oral cavities of 150 HIV-infected patients and cultured on Sabouraud-dextrose agar; 89 (59·3%) of 150 patients had positive culture for Candida and presented clinical sign of classical oral candidiasis. Totally, 102 morphologically distinct colonies were isolated from Candida positive cultures and subsequently identified by polymerase chain reaction and sequencing assay, presenting the following frequency: 54 C. albicans (52·9%), 16 C. dubliniensis (15·7%), 12 C. tropicalis (11·8%), 9 C. glabrata (8·8%), 7 C. kefyr (6·9%) and 4 C. africana (3·9%). Additionally, multiple Candida species were co-isolated from 13·5% (12/89) patients. Regarding the antifungal susceptibility test, which was performed by CLSI protocol (M27-A3/M27-S3), all Candida isolates were susceptible to amphotericin B and caspofungin, while some of them were resistant to fluconazole (17·6%; 16 C. albicans, 1 C. dubliniensis and 1 C. glabrata), itraconazole (16·7%; 15 C. albicans, 1 C. dubliniensis and 1 C. tropicalis) and voriconazole (5·9%; 5 C. albicans and 1 C. tropicalis). Collectively, our findings reinforce the urgent necessity to find new therapeutic agents to treat oral candidiasis in HIV-positive patients, especially due to the high incidence of azole-resistant Candida strains and the increased frequency of non-C. albicans species. SIGNIFICANCE AND IMPACT OF THE STUDY: The Candida species recovered from oral cavity of 150 Iranian HIV/AIDS patients and their antifungal susceptibility profiles were reported. Candida albicans was the commonest Candida species, followed by C. dubliniensis, C. tropicalis, C. glabrata, C. kefyr and C. africana. All Candida isolates were susceptible to amphotericin B and caspofungin, while resistance to azoles was detected. The growing drug-resistance profile reported in clinical isolates of C. albicans and non-C. albicans strains is a serious problem in hospitals worldwide. Consequently, the suitable antifungal choice to treat the HIV/AIDS population with oral candidiasis needs to be rethought and new therapeutic options must urgently arise.

Production of antimicrobial substances by Bacillus subtilis LFE-1, B. firmus HO-1 and B. licheniformis T6-5 isolated from an oil reservoir in Brazil.

AIMS: Forty Bacillus strains isolated from a Brazilian oil reservoir were tested against each other to select strains producing antimicrobial substances (AMS). Three strains, Bacillus subtilis (LFE-1), Bacillus firmus (H2O-1) and Bacillus licheniformis (T6-5), were selected due to their ability to inhibit more than 65% of the Bacillus strains tested. These three strains were also investigated for their capability to inhibit sulphate-reducing bacteria (SRB). Furthermore, physiological and biochemical characteristics of the antimicrobial compounds produced by the selected strains were determined. METHODS AND RESULTS: Among the forty strains tested, 36 (90%) strains were able to inhibit at least one Bacillus strain used as indicator in plate assays and three of them (LFE-1, T6-5 and H2O-1) were able to inhibit 65, 70 and 97.5% of the 40 strains studied here respectively. Clear zones of inhibition were observed when H2O-1 was tested against SRB-containing consortium T6-lab and Desulfovibrio alaskensis strain NCIMB 13491, while strain T6-5 was able to inhibit only the D. alaskensis strain. The three substances showed to be insensitive to different enzymes and chemicals, were heat stable and the substances produced by strains T6-5 and H2O-1 were active over a wide pH range. CONCLUSIONS: Three different AMS produced by Bacillus strains from an oil reservoir, two of them with activity against SRB, are presented here. SIGNIFICANCE AND IMPACT OF THE STUDY: The preliminary characterization of these AMS points to their potential use as biocides in the petroleum industry for controlling problems associated with SRB.