Traditionally recognized as environmental bacteria, Planctomycetes have just been linked recently to human pathology as opportunistic pathogens, arousing a great interest for clinical ...microbiologists. However, the lack of appropriate culture media limits our future investigations as no Planctomycetes have ever been isolated from patients' specimens despite several attempts. Several Planctomycetes have no cultivable members and are only recognized by 16S rRNA gene sequence detection and analysis. The cultured representatives are slow-growing fastidious bacteria and mostly difficult to culture on synthetic media. Accordingly, the provision of environmental and nutritional conditions like those existing in the natural habitat where yet uncultured/refractory bacteria can be detected might be an option for their potential isolation. Hence, we systematically reviewed the various natural habitats of Planctomycetes, to review their nutritional requirements, the physicochemical characteristics of their natural ecological niches, current methods of cultivation of the Planctomycetes and gaps, from a perspective of collecting data in order to optimize conditions and the protocols of cultivation of these fastidious bacteria. Planctomycetes are widespread in freshwater, seawater, and terrestrial environments, essentially associated to particles or organisms like macroalgae, marine sponges, and lichens, depending on the species and metabolizable polysaccharides by their sulfatases. Most Planctomycetes grow in nutrient-poor oligotrophic environments with pH ranging from 3.4 to 11, but a few strains can also grow in quite nutrient rich media like M600/M14. Also, a seasonality variation of abundance is observed, and bloom occurs in summer-early autumn, correlating with the strong growth of algae in the marine environments. Most Planctomycetes are mesophilic, but with a few Planctomycetes being thermophilic (50°C to 60°C). Commonly added nutrients are N-acetyl-glucosamine, yeast-extracts, peptone, and some oligo and macro-elements. A biphasic host-associated extract (macroalgae, sponge extract) conjugated with a diluted basal medium should provide favorable results for the success of isolation in pure culture.
Gemmata are Planctomycetes bacteria recalcitrant to traditional cultivation in the clinical microbiology laboratory and they have been seldom documented in patients. Based on previously known ...relationships of Planctomycetes with marine sponges, we designed a new culture medium A incorporating marine sponge skeleton of Spongia sp. to the standard culture medium; and culture medium B incorporating Spongia sp. skeleton heat aqueous filtrate into medium A; and inoculating the three culture media (standard, A and B) with Gemmata obscuriglobus DSM 5831
and Gemmata massiliana DSM 26013
in the presence of negative controls. Cultures were observed by naked eyes for 7 days and bacterial growth was quantified by microscopic observations and culture-based enumerations. Macroscopic observations at day-3 revealed a pink bacterial pellet in medium B tubes while standard medium tubes remained limpid until day-8. Growing Gemmata spp. bacteria in medium A yielded air bubbles released by bacterial respiration, whereas control tubes remained bubble-free. The number of colonies in standard medium (1.363 ± 115 for G. obscuriglobus, 1.288 ± 83 for G. massiliana) was significantly lower than those counted from medium B (2.552 ± 128 for G. obscuriglobus, 1.870 ± 112 for G. massiliana) and from medium A (2.851 ± 137 for G. obscuriglobus, 2.035 ± 163 for G. massiliana) (p < 0.10
) at day-2 incubation. At day-3 incubation, the number of colonies counted from supplemented media A and B increased up to one log than those counted from the control medium (p < 0.10
). Along the following day-4-7 incubation, the number of colonies counted from media A and B remained significantly higher compared to standard medium (p < 0.10
). These data indicate that incorporation of spongin-based marine sponge skeleton and heat aqueous filtrate of sponge skeleton significantly improved growth of Gemmata spp. bacteria. These observations pave the way towards improved isolation and culture of Gemmata spp. from environmental and clinical specimens.
This study aimed to evaluate the seroprevalence of anti-SARS-CoV-2 IgG and factors associated with the infection among PLWHIV over the first 12 months following the outbreak of COVID-19 in Burkina ...Faso.
A retrospective cross-sectional study of plasma samples collected from March 9, 2020, and March 8, 2021, at the outpatient HIV referral center, before the introduction of the SARS-CoV-2 vaccine in Burkina Faso.
Anti-SARS-CoV-2 IgG were detected in plasma using DS-ЕIA-ANTI-SARS-CoV-2-G (S) kit. Logistic regressions were used to compare SARS-CoV-2 specific immune responses between groups and within subgroups.
A total of 419 plasma were subjected to serological diagnosis. None of the participants was vaccinated against COVID-19 during the period of sample collection, and 130 samples were positive for anti-SARS-CoV-2 IgG, giving a prevalence of 31.0% (95% CI 26.6-35.7). The median CD4 cell count was 661 cells/μL (IQR,422-928). Retailers had half the risk of being infected compared to housemaids with an OR of 0.49 (p = 0.028, 95% CI 0.26-0.91). Likewise, the risk of infection was 1.69 times higher in patients on integrase inhibitors compared to that of patients on non-nucleoside reverse transcriptase inhibitors (p = 0.020, 95% CI 1.09-2.63).
Our study reveals a high seroprevalence among PLWHIV to SARS-CoV-2 during the first year of the pandemic. In addition, PLWHIV on integrase inhibitors are 1.69 times more likely to be infected than PLWHIV on non-nucleoside inhibitors, and this observation remains an intriguing topic that still needs to be clarified.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Timely diagnosis of Pulmonary Tuberculosis (PTB) is associated with good prognosis, but remains difficult in primary healthcare facilities and particularly in children and patients living with HIV. ...The aim of this study was to compare the GeneXpert ® MTB/RIF assay (Xpert) performed using a stool sample (3-5 g) and using the first Respiratory Tract Sample (RTS; i.e., sputum, bronchoalveolar or gastric aspirate; as normally done) concomitantly collected from 119 patients with suspected PTB to improve PTB diagnosis in Burkina Faso, a high tuberculosis burden country with limited resources. Overall, microbiological, microscopic and molecular analysis of the 119 first RTS and 119 stool specimens led to Mycobacterium tuberculosis complex detection in 28 patients (23 positive RTS cultures and 5 negative RTS cultures-RTS Xpert positive). When using the 28 clinical confirmed cases as reference standard, the sensitivities of the stool-based and RTS-based Xpert assays were not different (24/28, 85.7%, versus 26/28, 92.86%; p > 0.30), and 22 results were fully concordant. Considering the first RTS culture as the gold standard, the sensitivities of the stool-based and RTS-based Xpert assays to detect PTB in patients with positive RTS culture were 100% (23/23) and 91.3% (21/23), respectively (p >0.05). The stool-based Xpert assay specificity for excluding PTB was 99% (95/96) (compared with 95%, 91/96, when using RTS) and its negative and positive predictive values were 100% (95/95) and 96% (23/24), respectively. Compared with the 23 positive RTS cultures, the incremental yield rates of the RTS-based and stool-based Xpert assays were 4.2% (5/119) and 0.84% (1/119), respectively. Overall, our findings support using the stool-based Xpert assay as an alternative method for earlier PTB diagnosis, when RTS are difficult to obtain.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Gemmata spp. bacteria thrive in the same aquatic environments as free-living amoebae. DNA-based detection of Gemmata spp. sequences in the microbiota of the human digestive tract and blood further ...questioned the susceptibility of Gemmata spp. to phagocytes. Here, Gemmata obscuriglobus and Gemmata massiliana were co-cultured with the amoebae Acanthamoeba polyphaga, Acanthamoeba castellanii, Acanthamoeba griffini and THP-1 macrophage-like phagocytes. All experiments were performed in five independant replicates. The ratio amoeba/bacteria was 1:20 and the ratio THP-1/bacteria was 1:10. After a 2-hour co-culture, extracellular bacteria were killed by kanamycin or amikacin and eliminated. The intracellular location of Gemmata bacteria was specified by confocal microscopy. Microscopic enumerations and culture-based enumerations of colony-forming units were performed at T = 0, 1, 2, 3, 4, 8, 16, 24, 48 and 72 hours post-infection. Then, Gemmata bacteria were engulfed into the phagocytes' cytoplasmic vacuoles, more than (98 ± 2)% of Gemmata bacteria, compared to controls, were destroyed by phagocytic cells after a 48-h co-culture according to microscopy and culture results, and no positive culture was observed at T = 72-hours. Under our co-culture conditions, Gemmata bacteria were therefore susceptible to the environmental and host phagocytes here investigated. These data suggest that these Acanthamoeba species and THP-1 cells cannot be used to isolate G. massiliana and G. obscuriglobus under the co-culture conditions applied in this study. Although the THP-1 response can point towards potential responses that might occur in vivo, these responses should first bevalidated by in vivo studies to draw definite conclusions.
Planctomycetes bacteria are known to be difficult to isolate, we hypothesized this may be due to missing iron compounds known to be important for other bacteria. We tested the growth-enhancement ...effect of complementing two standard media with
culture filtrate on two cultured strains of
spp. Also, the acquisition of iron by
spp. was evaluated by measuring various molecules involved in iron metabolism.
and
were cultured in Caulobacter and Staley's medium supplemented or not with
culture filtrate, likely containing siderophores and extracellular ferrireductases. We performed iron metabolism studies with FeSO
, FeCl
and deferoxamine in the cultures with the
filtrate and the controls.
The numbers of
and
colonies on Caulobacter medium or Staley's medium supplemented with
culture filtrate were significantly higher than those on the standard medium (
< 0.0001). Agar plate assays revealed that the
colonies near
colonies were larger than the more distant colonies, suggesting the diffusion of unknown growth promoting molecules. The inclusion of 10
to 10
M FeSO
resulted in rapid
spp. growth (4-5 days compared with 8-9 days for the controls), suggesting that both species can utilize FeSO
to boost their growth. In contrast, deferoxamine slowed down and prevented
spp. growth. Further studies revealed that the complementation of Caulobacter medium with
culture filtrate and 10
M FeSO
exerted a significant growth-enhancement effect compared with that obtained with Caulobacter medium supplemented with
culture filtrate alone (
< 0.0122). Moreover, the intracellular iron concentrations in
and
cultures in iron-depleted broth supplemented with the
filtrate were 0.63 ± 0.16 and 0.78 ± 0.12 μmol/L, respectively, whereas concentrations of 1.72 ± 0.13 and 1.56± 0.11 μmol/L were found in the
and
cultures grown in broth supplemented with the
filtrate and FeSO
. The data reported here indicated that both
culture filtrate and FeSO
act as growth factors for
spp. via a potentiation mechanism.
Background: The emergence of antimicrobial resistance (AMR) within bacterial pathogens necessitates a local comprehension of the epidemiological context. This information is indispensable for both ...clinical therapeutic determinations and the reevaluation of prevailing care protocols. This study aimed to highlight the antibiotic susceptibility profile of uropathogenic bacteria isolated within a university hospital in Burkina Faso, with a focus on enhancing probabilistic antibiotic therapy for both community and hospital-based urinary tract infections (UTIs). Methodology: Data from cytological urine analysis and antimicrobial susceptibility testing spanning 29 months (January 2017 to May 2019) was retrospectively collected and systematically analyzed. Results: In both hospital and community based UTIs, Enterobacterales dominated, constituting 79.86% (81.27% vs. 79.11%) of isolates. This was followed by non-fermentative Gram-negative bacteria at 6.60% (6.35% vs. 6.88%) and Gram-positive cocci at 6.41% (7.98% vs. 5.57%). Escherichia coli (61.37%), Klebsiella pneumoniae (10.66%), and Enterobacter spp. emerged as the predominant pathogens in the same rank regardless of the origin of the ITUs. Imipenem (97.19%), amikacin (69.26%), ceftriaxone (58.44%), and ciprofloxacin (47.60%) displayed superior susceptibility against all uropathogens. Subtle but significant variations emerged between hospital and community strains' susceptibility to various antibiotics, including amoxicillin + clavulanic acid (26.05% vs. 32.26%), Imipenem (96.43% vs. 98.59%), and ciprofloxacin (45.51% vs. 51.41%). Conclusion: Penicillins showcased diminished efficacy against uropathogens, while resistance to fluoroquinolones escalated. The combined use of aminoglycosides and third-generation cephalosporins holds promise as an optimal probabilistic therapy for UTIs. Notably, the profiles of hospital and community UTIs showed substantial similarities in terms of implicated uropathogens, yet hospital strains demonstrated higher resistance levels.
PDF
