Journal of Infection in Developing Countries最新文献

Introduction: Hepatitis C virus (HCV) genotype 1 is a significant cause of hepatocellular carcinoma (HCC) in Vietnam. Direct-acting antivirals (DAAs) are effective in achieving sustained virologic response (SVR), potentially reducing HCC incidence. This study evaluated how DAA regimens affect HCC incidence in Vietnamese patients with chronic liver disease related to HCV genotype 1.

Methodology: A retrospective cohort study was conducted with 450 HCV-1 patients treated with DAAs at the Liver Clinic, University Medical Center Ho Chi Minh City, Vietnam. Patients were followed for a median duration of 0.5 years. Treatment regimens included combinations of NS5A inhibitors with NS3/4A protease inhibitors or NS5B polymerase inhibitors. Data on demographics, baseline clinical characteristics (e.g., alpha-fetoprotein, albumin levels), and liver function were collected before initiating DAA treatment. Follow-up data, including SVR rates and HCC incidence, were assessed at the end of treatment and during the post-treatment observation period (median follow-up of 0.5 years). This approach allowed us to compare pre-treatment baseline data with post-treatment outcomes to evaluate the impact of DAA therapy on HCC risk factors and incidence.

Results: SVR was achieved in 94.8% of patients, with an HCC incidence of 1.1% at 1 year for SVR patients, versus 6.5% for non-SVR patients. Significant risk factors for HCC included hypoalbuminemia, elevated alpha-fetoprotein levels, and non-SVR status.

Conclusions: DAAs significantly reduce HCC incidence in Vietnamese patients with HCV-1; however, ongoing surveillance is essential for high-risk patients.

Introduction: Phage therapy is a promising alternative for combating multidrug-resistant bacteria, including Acinetobacter baumannii (AB). However, the development of phage-resistant variants after treatment, particularly when using phage cocktails, poses a significant challenge. This resistance can hinder the effectiveness of future phage-based treatments against pathogenic AB.

Methodology: Three AB-specific phages-AB-phage 22, AB-phage 27, and AB-phage 32-susceptible to an AB isolate, designated ABU-3, were used as a model to study phage resistance development in AB following phage treatment. This study proposes a strategy to effectively eliminate pathogenic AB using an optimal multiplicity of infection (MOI), referred to as the MOI clearance value.

Results: The MOI clearance values required for complete elimination of ABU-3 were determined to be 10 for AB-phages 22 and 32 and 100 for AB-phage 27. Surviving ABU-3 colonies from lower MOI treatments were analyzed for phage resistance. ABU-3 treated with AB-phage 27 developed resistance to AB-phage 27 but remained susceptible to AB-phages 22 and 32. ABU-3 treated with AB-phage 22 developed resistance to AB-phage 22 but retained partial susceptibility to the other phages at reduced MOI. In contrast, ABU-3 treated with AB-phage 32 displayed complete resistance to all three phages.

Conclusions: These findings highlight a key challenge in phage therapy: insufficient MOI ratio can promote phage resistance. The distinct resistance profiles observed emphasize the importance of optimizing phage combinations and dosages to prevent resistance development during treatment.

Introduction: Drug-resistant Acinetobacter baumannii poses a global health crisis, especially in Asia. It has a propensity to become clonally endemic in healthcare settings. However, its clonal distribution in a broad geographic area is unclear.

Methodology: The clonality of A. baumannii was characterized nationwide by collecting 572 drug-resistant A. baumannii from 18 hospitals across Thailand regions between 2017-2018 and genotyping them by random amplified polymorphic DNA (RAPD) polymerase chain reaction (PCR) in association with carbapenemase genes data.

Results: The results depicted 12 types of RAPD banding. Strikingly, two types were predominant in all hospitals (79%). Of those, 96% harbored the blaOXA-23 gene. The banding pattern matched the preexisting strain in the institution, suggesting an ongoing nationwide circulation of the resistant clone. Interestingly, a unique banding type was identified in high proportion in two nearby hospitals in the northern region (21%, 53/252). Two isolates with the same banding pattern were also identified in a hospital in Bangkok, suggesting the possibility of transfer between regions. Most of the subset of isolates analyzed belonged to sequence type (ST) 2, the most prominent ST in the Asia-Pacific region.

Conclusions: This study demonstrated continuous dissemination of predominating A. baumannii clones across the country, and the emergence of endemic hospital-specific clones, all with high burdens of blaOXA-23; suggesting a strong selection for these resistance determinants. In addition, genotyping with RAPD can be a simple and cost-effective epidemiological tool with efficient discriminatory power for A. baumannii in developing countries.

Introduction: Parrot fever, caused by Chlamydia psittaci, is a zoonotic disease typically treated with tetracyclines. Omadacycline, a novel aminomethyl tetracycline, has limited reports on its efficacy in severe Chlamydia psittaci pneumonia in the literature.

Case presentation: We present a case of a patient with severe Chlamydia psittaci pneumonia showing symptoms of chills, high fever, shock, hepatic and renal insufficiency, and acute respiratory failure with copious yellow watery sputum. Chlamydia psittaci was confirmed by metagenomic next-generation sequencing (mNGS). Despite initial treatment with moxifloxacin and doxycycline, the patient did not improve and was subsequently discharged after receiving omadacycline.

Conclusions: Our findings highlight the potential of mNGS for rapid diagnosis of Chlamydia psittaci pneumonia and suggest omadacycline as a potential therapeutic option for severe cases that do not respond to conventional treatment.

Introduction: Non-tuberculous mycobacteria (NTM) are a diverse group of environmental microorganisms, most non-pathogenic. Most people come into contact with NTM during their lives. Still, the infection occurs in people with previous lung comorbidities, weakened immune systems, and the elderly. This study aims to analyze the clinical characteristics of patients with NTM.

Methodology: The research was conducted in the form of a retrospective study, which included 23 patients with a diagnosis of NTM who were treated at the Clinic for Tuberculosis and Interstitial Lung Diseases of the Institute of Pulmonary Diseases of Vojvodina in Sremska Kamenica from 2014 to 2023.

Results: Patients were predominantly male (15, 65.2%). The most common type of NTM was Mycobacterium xenopi in 8 patients (34.8%), as well as the way of establishing the diagnosis in patients who had negative direct microscopy and culture confirmation (12, 52.2%), followed by positive direct microscopy and culture confirmation (10, 43.5%). Smokers were the most frequent (10, 55.6%). The most common comorbidity was chronic obstructive pulmonary disease (10, 43.5%). A statistically significant difference was found in the frequency of the method of proof across different types of non-tuberculous mycobacterium infections (Fisher's exact test = 21.928; p = 0.006). Fatal outcomes were seen in 17.6% of patients.

Conclusions: A detailed history, evaluation of clinical features, radiological findings, and microbiological samples are required in patients with suspected NTM infection. Raising suspicion and speeding up diagnostic procedures in these patients is of great importance for the timely initiation of treatment and reduction of mortality.

Introduction: The coronavirus disease 2019 (COVID-19) pandemic has significantly accelerated the development of diagnostic techniques. Real‑time quantitative polymerase chain reaction (RT‑qPCR) was the method of choice for diagnosis and was considered as the gold standard. However, limited specificity of RT-PCR was noticed during the pandemic. This research aimed to develop a combined highly specific immune-based and highly sensitive molecular-based diagnostic technique.

Methodology: Groups of chicken were immunized with commercial severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) N, S, and E antigens. The IgY antibodies were purified from eggs using a High-Trap IgY affinity column. Three unique DNA barcodes were designed, synthesized, and amplified using 5'-amine-labeled forward primers. DNA barcodes purified form PCR products were coupled to IgY antibodies using the (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide) - N-hydroxysuccinimide (EDC-NHS) coupling chemistry. ELISA; SDS-PAGEs; immunoblot (IB); and uniplex-, duplex- and multiplex immuno-PCR (IPCR) were used to confirm system validity.

Results: Amplification of single barcodes using RT-PCR showed a Ct value of 15, with no significant variation when amplified in duplex or multiplex formats. Chicken IgY-DNA barcode conjugation and reactivity were verified using IB and ELISA. IPCR resulted in efficient amplification of all three DNA barcodes in uniplex, duplex, and multiplex formats after binding to commercial N, S, and E antigens.

Conclusions: The successful combination of the specific antibody-based techniques, low-cost chicken IgY antibodies, and RT-PCR sensitivity achieved in this study present a promising approach to meet the demand for sensitive and accurate diagnostics. This generic platform can be adopted in any analyte detection system.

Introduction: The hospital environment is an important source of nosocomial infections. Surfaces in the hospital facilities may be considered as microbial reservoirs that can cause patient contamination. This study aimed to evaluate the microbiological quality of surfaces and equipment in the Mohammed V Hospital, located in Al-Hoceima, Morocco.

Methodology: A total of 360 samples of surfaces were collected by swabbing from 5 service departments (intensive care unit (ICU), maternity, neonatology, operating room, and pediatric) over a period of 1 year (January-December 2021). The samples were analyzed at the provincial public health laboratory of Al-Hoceima. Isolation and identification of bacteria were performed according to conventional bacteriology methods.

Results: The results indicated that 34.4% (124/360) samples were contaminated. The ICU was the most contaminated service and the frequency of contaminated samples was 50%. The most contaminated sampling sites were soap for hand washing (27.4%), trolleys (25.8%), and sinks (22.6%). Gram-positive bacteria represented 51.6% of the contaminants. The most isolated bacteria were Staphylococcus aureus (50%), followed by Klebsiella pneumoniae (23.5%), and Pseudomonas aeruginosa (12.4%). Extended spectrum beta lactamase-producing Enterobacteriaceae represented 31.7% of the contaminants. Methicillin-resistant Staphylococcus aureus (MRSA) accounted for 17.6% of the contaminants.

Conclusions: This study provided important data that can guide the nosocomial infection control committee to manage the risks related to contaminated hospital surfaces through the establishment of an adequate risk analysis strategy.

Introduction: Livestock is vital to Angola's economy, with cattle farming being especially important in Bié Province. Productivity is hampered by tick (Ixodida: Ixodidae) infestation, causing damage and potential transmission of pathogens. Despite known tick diversity in Angola, recent data for Bié Province are lacking.

Methodology: A cross-sectional survey was conducted from January to August 2024 in Bié Province across 11 localities, covering commercial and family-based cattle systems. Systematic random sampling was used to examine 686 cattle for ticks during early dry and rainy seasons. Ticks were collected from 7 anatomical regions and morphologically identified; the data were analyzed for seasonal variation, spatial distribution, and gender ratio.

Results: A total of 3,136 adult ticks were collected from 686 cattle (30.3% infestation rate). Ten species across 3 genera were identified, namely Rhipicephalus, Amblyomma, and Hyalomma. Rhipicephalus evertsi mimeticus was the most prevalent (27.9%), followed by R. evertsi evertsi (13.2%), R. (Boophilus) decoloratus (13.1%), and Amblyomma variegatum (12.3%). Tick abundance was quite similar between seasons, and females predominated (51.1%). Infestation varies by commune.

Conclusions: The findings reveal substantial tick diversity in Bié Province and confirm ongoing exposure of cattle to multiple species.

Introduction: Acute gastroenteritis (AGE) remains a major public health concern for the pediatric population. Diarrheal surveillance in Venezuela following the implementation of the rotavirus vaccines has been discontinuous, resulting in a lack of knowledge of the true epidemiological burden. This study investigated retrospectively the occurrence of enteropathogenic virus infections and potential changes in the etiological pattern of diarrheal disease in Venezuelan children during the post-vaccination period.

Methodology: Stool samples from 150 children with AGE and 148 controls under five years old collected in 2012-2013, were analyzed using molecular assays by rotavirus, norovirus, human adenovirus, human astrovirus, and Aichi virus. Clinical and sociodemographic associations were assessed.

Results and conclusions: At least one virus was found in 66 (44%) of the children with AGE, and in 12 (8.1%) of the control group (p < 0.0001), mostly under 24 months old. Norovirus and rotavirus prevailed significantly in the AGE group (19.3% and 18%, respectively) compared to the control group (4.7% and 0%, respectively) (p < 0.001). Astrovirus, adenovirus, and Aichi virus were found in 5.3% or less of the children. Malnutrition, lack of breastfeeding, absence of rotavirus vaccination, and lower socioeconomic status were more frequent among AGE children than in controls (p = 0.014). This study suggests that rotavirus continued circulating widely even after vaccine introduction. It emphasizes the importance of norovirus and other viruses (adenovirus, astrovirus, and Aichi virus) as potentially emerging causes of pediatric diarrhea. Future strategies for precise health management and prevention of viral diarrhea should include surveillance using molecular methods alongside sanitation efforts and measures to reduce poverty and malnutrition.

Introduction: The objectives of this study were to determine the rates of biofilm formation by Pseudomonas aeruginosa (n: 136) isolates from different samples collected from intensive care patients; and to determine the synergistic effects of the combination of ceftazidime and colistin, and the inhibitory effect of baicalin on biofilm formation in strong biofilm-producing bacteria (3+).

Methodology: Previous studies have performed biofilm grading based on microplate absorbance measurement to phenotype the biofilm formation rate. The in vitro synergistic efficacy of the combination of colistin and ceftazidime was evaluated using the checkerboard method for strains with 3+ biofilm test results. In addition, sub-minimum inhibitory concentration (sub-MIC; MIC/2, MIC/4, MIC/8) values of the biofilm inhibitory effect of baicalin were determined.

Results: The biofilm microplate method identified 5.15% of the isolates producing strong (3+) biofilms. Baicalin inhibited biofilm formation by 67.00-90.64% at sub-MIC concentration of 512 µg/mL, in 7 strong biofilm-producing isolates. These findings suggest that baicalin is a potential adjunctive therapy for disrupting biofilms, although the combination of ceftazidime and colistin may not be effective in this context.

Conclusions: No synergistic effect of ceftazidime and colistin antibiotics was detected in high biofilm-producing P. aeruginosa isolates from an intensive care unit, and it was determined that certain concentrations of baicalin were effective in biofilm formation.