Indian Journal of Medical Microbiology最新文献

Purpose: Dengue virus, a major global health concern, exhibits significant genetic diversity, leading to distinct serotypes and genotypes. Dengue is the second most common disease spread by mosquitoes that infect humans, after malaria. In recent decades, there has also been a shift in the tendencies of virus transmission from urban to peri-urban and rural settings. This research study focuses on the identification and characterization of dengue virus serotypes and genotypes.

Methods: In this study specimens collected in one year were first subjected to serological assay (NS1 and IgM) and subsequently theNS1 positive samples were subjected to identification and characterization of the prevalent dengue virus serotypes and genotypes.

Results: During the year 2021, a total of 933serum samples were tested, out of which 75 were found positive for NS1 antigen and 135 were positive for Dengue IgM antibody by ELISA. The dengue serotype specific Real-Time RT-PCR Assay detected all four serotypes in the NS1-positive samples, indicating their presence in this region. Of these, DEN-1 was detected in 4 (7.8%), DEN-2 in 26 (50.9%), DEN-3 in 20 (39%), DEN-4 in 1 (1.9%). Out of 51Real-Time RT-PCR positive samples, 33 were found positive by conventional PCR for genotyping by targeting the capsid-preMembrane (C-prM)region. The genotyping result showed that DENV-1 serotype clustering with GIII, DEN-2 serotype clustering withwide range of genotypes such as IVa, IVb, and IVc, DEN-3 clustering with GIII genotype and DEN-4 serotype showed GIII genotype.

Conclusions: This study provides the recent details about the circulating serotypes along with prevalent genotypes in this region.

We report a rare case of Listeria ivanovii in elderly immunocompromised man with chronic kidney disease from South India, which was identified by conventional methods as well as MALDI-TOF and confirmed with 16S rRNA sequencing. In addition, literature search was done and the 10 cases of Listeria ivanovii infections reported earlier were discussed.

Background: Neonatal sepsis continues to be a leading cause of mortality among the NICU admitted neonates. The most common causative organisms have been proven to be hospital-acquired organisms.

Aims and objectives: This study was planned with aim of understanding the pathological colonization of neonatal skin and associated risk factors as well as finding a possible correlation between blood culture isolates and neonatal skin colonizers and their antimicrobial resistance patterns.

Methods: This prospective cohort study was conducted at a tertiary care centre in Northern India from January 2021 to June 2022. The study participants were 50 pre-term neonates and 50 term neonates, who were born in our hospital and subsequently admitted to the NICU. Skin swabs, taken from 5 body sites within 24 h of birth and at discharge, were cultured for isolation of pathological bacteria. Neonates were followed-up during their hospital stay for observing any occurrence of blood culture positive sepsis.

Results: Out of 100 neonates, 31 pre-term and 28 term neonates were colonized within 24 h of birth while almost all were colonized by discharge. Posterior auricular fossa was the most colonized site. Coagulase Negative Staphylococcus (n = 195) and Escherichia coli (n = 51) were the most common isolates. Risk factors found to be significantly associated with colonization were low birth weight (<2500g), premature rupture of membranes (PROM), invasive mechanical ventilation and positive urine and vaginal cultures of mothers. Neonates with culture positive sepsis also had colonization with MDROs.

Conclusions: Neonatal skin colonization and their antimicrobial resistance rates increased over the course of hospital stay, having a possible contribution towards culture positive sepsis.

Background: Vancomycin has been the preferred treatment for MRSA infections. However, newer drugs are necessary due to the increasing prevalence of MRSA isolates that are less susceptible to vancomycin. Levonadifloxacin and its prodrug alalevonadifloxacin, novel quinolones with broad spectrum anti-MRSA activity. They are approved in India for the treatment of skin and soft-tissue infections, bacteraemia, and diabetic foot infections.

Materials and methods: A total of 456 MRSA (Methicillin-resistant Staphylococcus aureus) isolates, including 333 isolates from JIPMER and 123 isolates from other tertiary care centers collected between January to December 2022, underwent susceptibility testing to levonadifloxacin by disc diffusion method. The study isolates included 29 h-VISA. Fifty one blood isolates were also subjected to E-test and their results were compared to the gold standard, broth micro dilution (BMD).

Result: All 456 isolates were found to be susceptible to levonadifloxacin by disc diffusion. Levonadifloxacin demonstrated potent activity against MRSA strains isolated from blood (n = 51) with an MIC₅₀ and MIC₉₀ of 0.38 and 0.5 μg/mL by E-test, respectively. Similarly, it demonstrated an MIC₅₀ and MIC₉₀ of 0.5 & 1 μg/ml by BMD.

Conclusion: The present study demonstrated 100 % susceptibility to levonadifloxacin among the tested isolates of MRSA, highlighting its promising clinical potential for treating infections caused by this organism. Furthermore, the study recorded a concordance of 100 % between disc diffusion and Etest method with BMD, indicating the reliability of these methods.

Introduction: Viral infections are the predominant cause of acute hemorrhagic conjunctivitis (AHC) across the globe. From July to August of 2023, a large-scale conjunctivitis outbreak was witnessed in India, affecting a large number of individuals. The present study was initiated to identify the causative agent responsible for the AHC outbreak in Kalburgi district of Karnataka state.

Methodology: Conjunctival and throat swabs were collected from AHC patients from a tertiary care hospital in Kalburgi from August to September 2023. After total viral RNA extraction from all the samples, reverse transcriptase PCR was performed using 5' non-coding regions of the enterovirus (EV) genome. The positive samples were further subjected to PCR using EV type-specific primers of Coxsackie A-24 variant (CA24v) and enterovirus-70 (EV-70). EV negative samples were also tested for human adenovirus. Five representative CA24v-positive samples were subjected to partial sequencing and phylogenetic analysis.

Results: Thirty-three AHC patient samples were included in the testing and analysis. EV was detected among 54.5 % (18/33) of the patients and all were found to be CA24v, while no EV-70 or human adenovirus was detected. Partial 3C-proteinase sequencing revealed that the CA24v strains from Kalburgi were closely clustered and had 99 % sequence identity with CA24v strains reported from China in 2023. However, the Kalburagi strains were 90.3-93.2 % identical to previously reported Indian strains.

Conclusion: To summarize, CA24v was identified as an etiological agent responsible for the recent acute hemorrhagic conjunctivitis outbreak in Kalburgi. The CA24v strain detected was closely related to the currently circulating Asian strains.

Soil transmitted helminth (STH) infections remain prevalent in India despite the ongoing deworming program. Here, we report a case of triple infection of Ascaris lumbricoides, Ancylostoma duodenale, and Strongyloides stercoralis, in a young asymptomatic and apparently immunocompetent female presenting with aluminium phosphide poisoning. Except for severe anaemia, the only other indicators of chronic infection were occasional abdominal pain and self-limiting loose stools. She was successfully treated for her conditions. This case highlights that despite regular deworming programs in children, STH may continue to infect adults in endemic areas and may be relevant to their well-being.

Introduction: Ralstonia pickettii is a non-fermenting gram-negative bacillus rarely associated with hospital-acquired infections. The study aimed to characterise the clinical profile and outcomes of R. pickettii bacteremia cases.

Methodology: We retrospectively reviewed the hospital records to collect the details of the clinical profile and outcomes of patients with R. pickettii bacteremia between March and November 2021.

Results: Twenty-four patients were found to have Ralstonia pickettii bacteremia between March and May 2021. The cases were distributed across the hospital. All isolates were found to have similar antimicrobial susceptibility. The same organism with similar susceptibility was found to be in distilled water used to prepare in-house disinfectant and antiseptic agents. Commercial preparations replaced in-house solutions all over the hospital as a corrective measure. The distilled water tank was renovated, and repeat samples were found to be satisfactory. There were no further reports of Ralstonia pickettii between May and November 2021.

Conclusion: We report this to highlight the possibility of infection with this rare pathogen and to increase awareness of the importance of appropriate infection control measures.

We describe a rare case of an eleven-year-old child with undiagnosed underlying Crohn's disease who contracted Vibrio pelagius. Though the exact source remained undetermined, the child may have acquired it through infected sea food. Automated system failed to exactly identify the isolated organism; we used detailed biochemical tests for identification. Early diagnosis and identification allowed for efficient treatment plan and the clinical improvement of the child. This case report will give insight to clinical microbiologists for identifying such uncommon bacteria by using biochemical assays in addition to automated systems especially, in those with underlying bowel illnesses.

Objective: The antifungal audit aimed to evaluate antifungal usage in a tertiary care center. It focused on patient profiles, the appropriateness of antifungal use, associated adverse drug reactions, reasons for suboptimal usage, and the economic burden caused by prolonged non-optimal antifungal use.

Methodology: Conducted at All India Institute of Medical Sciences, New Delhi, India from January 2019 to December 2020, the study evaluated systemic antifungal use in 100 hospitalized adults with invasive fungal infections. Data collected included patient characteristics, evidence of disease, antifungal agents used, drug ADRs, appropriateness, and economic impact. Antifungal use was assessed using a predefined score (score <10 considered non-optimal), and ideal therapy duration was calculated based on treatment guidelines (IDSA & ECIL).

Results: Optimal antifungal use was observed in 66.0 % of cases. Common reasons for non-optimal use included alternate drug selection (18 %), inappropriate dosage (12 %), lack of adjustment after microbiological results (14 %), and incorrect therapy duration (16 %). Targeted antifungal therapy was observed in 39 out of 100 patients, while pre-emptive antifungal therapy was used in 32 out of 100 patients. Voriconazole (35.1 %), caspofungin (23.1 %), and liposomal amphotericin B (20.1 %) were commonly prescribed. Liposomal amphotericin B had the highest adverse reaction rate (81.4 %). The total cost of antifungal therapy for 100 patients was ₹67,06,840 (approximately 80,350 $), with non-optimal prolonged therapy leading to an additional economic burden of ₹1,149,191 (approximately 13,841 $). Overall, 748 (39.7 %) day of therapy were non-optimal, contributing to 17.1 % of the total cost of antifungal therapy.

Conclusion: We observed non-optimal use of antifungal agents in 34 % of the study participants. The study results show that the antifungal audit enhances stewardship by pinpointing causes of non-optimal use, ensuring adherence to prescribing standards, optimizing clinical outcomes, and minimizing drug-related toxicities in tertiary care centres.

Purpose: In this prospective study incidence of Mycoplasma pneumoniae (M. pneumoniae) infection was investigated in children with community-aquired lower respiratory tract infections (LRTIs) using methods such as serology, nested PCR (polymerase chain reaction), and multiplex PCR analysis.

Methods: M. pneumoniae infection was investigated among 200 children with LRTIs, ages 2 months to 12 years,. Blood samples were taken for M. pneumoniae antibodies both during admission and four to six weeks following enrollment. Nested and multiplex PCR analysis was performed to identify M. pneumoniae from nasopharyngeal aspirates (NPAs).

Results: Infection due to M. pneumoniae was noted in 29 children (74.35 %) < 5 years of age and in 10 children (25.65 %) aged ≥5 years. The relationship between M. pneumoniae and age was statistically significant in the age group of children under five years [P = 0.004]. No statistically significant difference was seen between male and female children [P = 0.91]. Clinical and radiological results and M pneumoniae infection did not demonstrate any statistically significant correlation with the exception of the presence of statistically significant infiltrates (P = 0.04). In 39 (19.5 %) children, M. pneumoniae was found using a combination of multiplex PCR, nested PCR, and serology. Serology sensitivity was 66.67 %, specificity was 88.56 %, positive and negative predictive values were 36.36 % and 96.41 %, respectively, when using nested PCR as the diagnostic criteria.

Conclusions: In summary, our research established the critical role of M. pneumoniae infection in community-acquired LRTIs in children particularly in children under five years. There was an association between wheezing and acute M. pneumoniae infection. Multiplex PCR, nested PCR, and serology are used in conjunction to help diagnose M. pneumoniae infection in children with community-acquired LRTIs.