Small molecule bio-signature in childhood intra-thoracic tuberculosis identified by metabolomics.

The diagnosis of pediatric tuberculosis (TB) remains a major challenge, hence the evaluation of new tools for improved diagnostics is urgently required. We investigated the serum metabolic profile of children with culture-confirmed intra-thoracic TB (ITTB) (n = 23) and compared it with those of non-TB controls (NTCs) (n = 13) using proton NMR spectroscopy-based targeted and untargeted metabolomics approaches. In targeted metabolic profiling, five metabolites (histidine, glycerophosphocholine, creatine/phosphocreatine, acetate, and choline) differentiated TB children from NTCs. Additionally, seven discriminatory metabolites (N-α-acetyl-lysine, polyunsaturated fatty acids, phenylalanine, lysine, lipids, glutamate + glutamine, and dimethylglycine) were identified in untargeted metabolic profiling. The pathway analysis revealed alterations in six metabolic pathways. The altered metabolites were associated with impaired protein synthesis, hindered anti-inflammatory and cytoprotective mechanisms, abnormalities in energy generation processes and membrane metabolism, and deregulated fatty acid and lipid metabolisms in children with ITTB. The diagnostic significance of the classification models obtained from significantly distinguishing metabolites showed sensitivity, specificity, and area under the curve of 78.2%, 84.6%, and 0.86, respectively, in the targeted profiling and 92.3%, 100%, and 0.99, respectively, in the untargeted profiling. Our findings highlight detectable metabolic changes in childhood ITTB; however, further validation is warranted in a large cohort of the pediatric population.

Tick-tock, beat the clock: comparative analysis of disc diffusion testing with 6-, 10-, and 24-h growth for accelerated antimicrobial susceptibility testing and antimicrobial stewardship.

Disc diffusion testing by Kirby-Bauer technique is the most used method for determining antimicrobial susceptibility in microbiological laboratories. The current guidelines by The Clinical and Laboratory Standards Institute (CLSI) 2022 specify using an 18- to 24-h growth for testing by disc diffusion. We aim to determine if using an early growth (6 h and 10 h) would produce comparable results, thus ultimately leading to reduced turnaround time. Six-hour, 10-h, and 24-h growths of 20 quality control strains and 6-h and 24-h growths of 48 clinical samples were used to perform disc diffusion testing using a panel of appropriate antimicrobial agents. Disc diffusion zone sizes were interpreted for all and comparative analyses were performed to determine categorical agreement, minor errors (mE), major errors (ME), and very major errors (VME) according to CLSI guidelines. On comparing with the standard 24 h of incubation, disc diffusion from 6-h and 10-h growths of quality control strains showed 94.38% categorical agreement, 5.10% mE, 0.69% MEs, and no VMEs. Disc diffusion testing for the additional 40 clinical samples yielded a similarly high level of categorical agreement (98.15%) and mE, ME, and VME of 1.29%, 1.22%, and 0% respectively. Disc diffusion testing using early growth is a simple and accurate method for susceptibility testing that can reduce turnaround time and may prove to be critical for timely patient management.

Evaluation of SARS-CoV-2 Specific IgG Antibodies in Individuals Vaccinated with Covaxin (BBV152): An Independent Assessment.

Post vaccination with Covaxin (BBV152), Serum from healthcare professionals of Microbiology Department at apex tertiary referral hospital of India were tested for SARS-CoV-2 specific IgG antibodies. 70% individuals at 14-30 days, 63.1% individuals at 30-60 days but only 36.8% individuals at 60-90 days after second dose of vaccine had detectable SARS-CoV-2 spike protein specific IgG antibodies. However, 80% individuals at 14-30 days, 89.4% individuals at 30-60 days while 94.7% individuals at 60-90 days after second dose of vaccine had detectable SARS-CoV-2 whole cell antigen specific IgG antibodies. Males were lacking SARS-CoV-2 spike protein specific IgG antibodies in higher proportion than females and had lower index wherever detected. Age and co-morbidities were non-significant factors for post vaccination IgG response but not in breakthrough infection. 8.3% individuals developed mild COVID-19 symptoms post 14-90 days of second dose and none had severe COVID-19. SARS-CoV-2 spike protein specific IgG antibodies induced by Covaxin are drastically reduced in 60-90 days among fully vaccinated individuals which could be a potential risk for breakthrough SARS-CoV-2 infection, if not severe COVID-19. It may be essential to have additional antigenic stimulations/boosters for continued protection.

Virulence gene mutations as a differentiator of clinical phenotypes: insights from community-acquired uropathogenic Escherichia coli.

Uropathogenic Escherichia coli (UPEC) remains an important cause of urinary tract infection during pregnancy. Multiple molecular virulence determinants and antibiotic resistant genes facilitate its pathogenesis and virulence phenotype. Hence it is hypothesized that there will be considerable variation in genes among the isolates from symptomatic as well as asymptomatic bacteriuria (ABU) during pregnancy. The aim of this study was to decipher the genetic variation among the two phenotypes. Six different UPEC isolates collected from urine specimens of consecutive pregnant females (five, symptomatic bacteriuria and one, ABU) were tested for their growth kinetics, and biofilm formation. A total of 87 virulence determinants and 56 antibiotic resistance genes were investigated using whole-genome sequencing, to identify putative drives of virulence phenotype. In this analysis, we identified eight different types of fully functional toxin antitoxin (TA) systems [HipAB, YefM-YoeB, YeeU-YeeV (CbtA), YhaV-PrlF, ChpBS, HigAB, YgiUT and HicAB] in the isolates from symptomatic bacteriuria; whereas partially functional TA system with mutations were observed in the asymptomatic one. Isolates of both the groups showed equivalent growth characteristics and biofilm-formation ability. Genes for an iron transport system (Efe UOB system, Fhu system except FhuA) were observed functional among all symptomatic and asymptomatic isolates, however functional mutations were observed in the latter group. Gene YidE was observed predominantly associated with the biofilm formation along with few other genes (BssR, BssS, YjgK, etc.). This study outlines putative critical relevance of specific variations in the genes for the TA system, biofilm formation, cell adhesion and colonization among UPEC isolates from symptomatic and asymptomatic bacteriuria among pregnant women. Further functional genomic study in the same cohort is warranted to establish the pathogenic role of these genes.

HIV testing & diagnosis in 2020 at the apex tertiary referral hospital of India: impact of COVID-19 pandemic.

Timely HIV testing and diagnosis are necessary to prevent the development of AIDS and interrupt its transmission in society. We collected the data on HIV testing and diagnosis in 2020 and compared it with preceding years to examine how COVID-19 pandemic-related restrictions impacted HIV services. The number of people who underwent HIV testing at the apex tertiary referral hospital of India in 2020 reduced by 57% compared to 2019 or the average/year during 2019-2016. Hence, the diagnosis of new HIV infections decreased by 52% compared to 2019 and 54% compared to the average/year during 2019-2016. Provider-initiated testing and diagnosis were more affected than client-initiated. There was a non-significant change in the rate of HIV detection among tested individuals. The male testing saw a more notable drop than female testing. HIV testing between ≥50 years and ≤14 years was more affected than other age groups. The transmission via regular partner/spouse increased, whereas it decreased via heterosexual commercial sex workers.

Antibiotic resistance of uropathogens among the community-dwelling pregnant and nonpregnant female: a step towards antibiotic stewardship.

BACKGROUND: Indiscriminate and widespread use of antibiotics has resulted in emergence of many antibiotic-resistant organisms. Antibiotic administration during pregnancy is mostly avoided, unless there is compelling medical condition. We hypothesized that the uropathogens isolated from pregnant women would be more susceptible to antibiotics compared to those isolated from nonpregnant women, thus will be helpful in formulating separate empiric guideline for pregnant women based on the resistance pattern. METHODS: This was a prospective cross-sectional study conducted over a period of 2 years in which females with the clinical diagnosis of either cystitis or asymptomatic bacteriuria during pregnancy were included from the community settings. Uropathogen species and their antimicrobial resistance pattern were compared between the pregnant and nonpregnant groups. After accounting for centre-to-centre variation and adjusting for age and socio-economic status, the adjusted odds ratio for antibiotic resistance was calculated and compared between pregnant and nonpregnant women using logistic regression analysis. RESULTS: A total of 1758 women (pregnant: 43.3%; nonpregnant: 56.6%) were screened in the study over a period of 2 years, out of which 9.3% (163/1758) were having significant bacteriuria. Escherichia coli and Klebsiella pneumoniae were the two commonest uropathogen in both the groups; their prevalence being 83.6% in pregnant women and 85.2% in nonpregnant women, respectively. Resistance against ampicillin, cefixime, cefoxitin, ceftazidime, ceftriaxone and amoxicillin-clavulanic acid were found significantly lower in the pregnant women compared to nonpregnant. After adjusting the age and socio-economic status accounting for centre-to-centre variation, the odds of resistance for cefixime, amoxicillin-clavulanic acid and co-trimoxazole were found lower and statistically significant among the pregnant women group. CONCLUSIONS: The antimicrobial resistance was significantly higher among the community-dwelling nonpregnant women compared to pregnant women in case of few antibiotics. The study highlighted the need of building local antibiogram that could help to initiate the empirical treatment and thus prevent emergence of antimicrobial resistance.

Microbial and Antibiotic Susceptibility Profile among Isolates of Clinical Samples of Cancer Patients Admitted in the Intensive Care Unit at Regional Tertiary Care Cancer Center: A Retrospective Observational Study.

Cancer patients in intensive care unit (ICU) are vulnerable for developing multidrug resistant nosocomial infections. The antimicrobial resistance due to inappropriate use of antibiotics results in significant morbidity and mortality in these cancer patients. The present retrospective study was done to describe the antimicrobial sensitivity pattern of common organisms in isolates of clinical samples of patients admitted in ICU at our tertiary care cancer center. MATERIALS AND METHODS: The study was carried out at ICU of a regional tertiary care cancer center for a period of 1 year from October 2016 to September 2017. All clinical samples were collected and processed for culture and antibiotic susceptibility testing were carried out on isolates as per Clinical Laboratory Standard Institute guidelines. RESULTS: A total of 644 specimens were collected. Escherichia coli, Acinetobacter spp., Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus spp. were most commonly encountered. In positive bacterial cultures, majority were Gram-negative isolates (84.14 %). Klebsiella was the most common gram-negative isolate (34.78%) and Enterococcus spp. were the most common Gram-positive isolates (61.53%). A high level of resistance to various antibiotics was noted among Gram-negative bacteria compared to Gram-positive isolates. Majority of the Gram-negative isolates were sensitive to Imipenem, Meropenem, and Colistin sensitivity among Gram-negative isolates was 100%. Linezolid, Teicoplanin and Vancomycin were most sensitive antimicrobials against the Gram-positive bacteria. CONCLUSION: Regular monitoring of the pattern of resistance of bacteriological isolates in cancer patients is critical to develop antibiotic policy to combat these infections and reduce morbidity and mortality. HOW TO CITE THIS ARTICLE: Garg VK, Seema M et al. Microbial and Antibiotic Susceptibility Profile among Isolates of Clinical Samples of Cancer Patients admitted in the Intensive-care Unit at Regional Tertiary Care Cancer Center: A Retrospective Observational Study. Indian J of Crit Care Med 2019;23(2):67-72.

HIV-TB Cross-referral and Collaborative Strategy: 8 Years of Our Experience from An Urban Health Centre in North India.

BACKGROUND: Human immunodeficiency virus (HIV) and tuberculosis (TB) epidemics continue to fuel each other and with dual infections with these two deadly diseases on the rise, it becomes imperative to devise effective HIV-TB collaborative strategies. The present study was designed to evaluate the existing HIV-TB cross-referral mechanism at an urban health centre; to determine HIV sero-prevalence among pulmonary TB patients referred from chest clinic to the integrated counselling and testing centre (ICTC); and to evaluate the TB suspects referred from ICTC to the chest clinic for a possible TB aetiology. METHODS: The present study was a retrospective analysis of HIV-TB cross-referrals whereby a line list of all the patients referred under this strategy from January 2006 to December 2013 was retrieved and analysed. RESULTS: A total of 3726 TB cases were referred to the ICTC and 641 TB suspects were identified by ICTC counsellors and referred to the chest clinic during this period. HIV sero-prevalence among TB patients was 2.8% (106 of 3726) and TB prevalence among HIV sero-positive and sero-negative TB suspects was 9.3% (10/108) and 4.3% (9/211), respectively (p=0.07). HIV prevalence was found to be significantly higher among male (n=2024) than among female (n=1702) TB patients (4.4% versus 0.9%; p<0.0001). Only 319 of 641 (49.8%) ICTC patients referred to the chest clinic reached there. CONCLUSION: Our study highlights the strong need to scale up the integration and partnership between HIV and TB programmes for better and integrated diagnosis and care of HIV-TB co-infected patients.

Detection of Aminoglycoside Modifying Enzyme (AME) genes in Acinetobacter baumannii isolates and the inhibitory effect of efflux pump activity on drug susceptibility pattern.

INTRODUCTION: The development of aminoglycoside modifying enzymes (AMEs) and increased efflux activity are considered important aminoglycosides resistance mechanisms. AIM: This study is focused on the detection of the AMEs gene and assessing the effect of efflux pump inhibitor on the reversal of A. baumannii drug susceptibility. METHODOLOGY: Bacterial DNA was amplified using AMEs gene-specific primers. Isolates were also investigated for efflux pump activity using efflux pump inhibitor (EPI) i.e. Carbonyl cyanide m-chlorophenyl hydrazone (CCCP) and the impact of both mechanisms was analyzed. RESULTS: Among A. baumannii isolates, 55% isolates (n â€‹= â€‹22/40) were identified to have aminoglycoside modifying enzymes genes; ant(3')-I gene (50%, 11/22), aac(6')-Ib gene (45.4%, 10/22), aph(3')-I gene (18.1%, 4/22) and aac(3)-I (9.1%, 2/22). Total 70% isolates have shown MIC alteration in different classes of drugs in response to EPI-CCCP. Such alteration was found in 100% amikacin sensitive and 58.6% amikacin resistant, 93.7% and 57.1% gentamicin sensitive and resistant isolates respectively. CONCLUSION: The presence of aminoglycosides modifying enzymes was frequent among aminoglycosides resistant A. baumannii isolates and the coexistence of efflux pumps activity also plays an important role to increase drug resistance. REPOSITORIES: Genbank and their accession numbers are MT903331[aac(3)-I], MT903332 MT903333 [ant(3')-I], MT903334, MT903335 [aph(3')-I)] and MT903336, MT940242 [ aac(6')-Ib].

A Quality Improvement (QI) initiative in diagnostic stewardship of urine culture in an era of Laboratory Information Systems (LIS).

Standard urine culture is the gold standard for diagnosing urinary tract infections (UTIs) but fails to differentiate true UTI from asymptomatic bacteriuria, which is important to prevent the overuse of antibiotics. Correlation with the presence or absence of pyuria can be helpful in giving a hint of the true situation. With the help of Laboratory Information System (LIS), patients' urinalysis reports can be conveniently accessed and compared simultaneously with appropriate reports. In our study, a quality improvement initiative was planned for appropriate reporting of urine culture and antimicrobial susceptibility testing using information obtained through LIS.

Antimicrobial efficacy of eravacycline against emerging extensively drug-resistant (XDR) Acinetobacter baumannii isolates.

PURPOSE: Drug-resistant Acinetobacter baumannii is an emerging threat. This study has been conducted to observe the efficacy of eravacycline along with the RND-efflux pump system. METHODS: A cross-sectional study was done collecting 48 clinical isolates of Acinetobacter baumannii. MICs of 15 antibiotics were detected along with BMD of tigecycline and eravacycline. PCR products of drug-resistant regulatory genes were sequenced and analyzed. RESULTS: Of the total 48 Isolates, 35 (72.91%) were XDR and 13 (27.08%) were MDR. Out of all, 60.41% of isolates were found to be susceptible to eravacycline by BMD according to both FDA and EUCAST guidelines. A 2-fold decline of MIC50/90 was observed with the use of eravacycline compared to tigecycline. RND-efflux genes like AdeC in 30 (62.5%) isolates and Regulatory gene AdeS in 29 (60.41%) isolates were detected, explaining the existing resistance mechanism. CONCLUSIONS: XDR Acinetobacter poses an escalating threat due to its resistance to multiple antibiotics, raising serious concerns in healthcare settings. Eravacycline is an encouraging new drug for empirical use in severe infection caused due to the same. Molecular investigation and strict antimicrobial stewardship should be followed to control the emergence, and a better understanding of mechanisms of resistance to prevent the spread of drug-resistant isolates.

The Gram stain: Implication in blood culture reporting.

Bloodstream infections are life-threatening. They are responsible for prolonged hospital stays and high healthcare costs. Clinical microbiology has an essential role to play in its management. Direct Gram-stain reporting from positive blood culture bottles has been found helpful. We aimed to evaluate the use of the automated blood culture system in adjunct to the conventional Gram-stain technique, with a direct antimicrobial susceptibility test on the second day. Concordance was highly satisfactory.

Genome profiling of uropathogenic E. coli from strictly defined community-acquired UTI in paediatric patients: a multicentric study.

BACKGROUND: Urinary tract infection (UTI) in children is a common bacterial infection. The emergence of extended-spectrum beta-lactamases (ESBLs) poses a major challenge against the treatment of uropathogens. We aimed to characterize the E. coli isolates recovered from children with UTI for their resistance profile and circulating sequence types (ST). METHODS: Children (> 1.5-18 years of age) from different community health centres of India with symptoms of UTI were enrolled. Isolates causing significant bacteriuria were identified by Matrix-Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) and tested for antimicrobial susceptibility by the automated system, VITEK-2 (Biomeriux, Durhum, US). Nineteen E. coli isolates (15 ESBL positive and 4 ESBL negative) were sequenced in Oxford Nanopore platform followed by core-genome phylogeny, accessory genome cluster analysis, identification of sequence types, mobile genetic elements, genetic antimicrobial resistance markers. The correlation between detection of antimicrobial resistance genes with phenotypic resistance profiles was also investigated. RESULTS: Eleven percent of children had significant bacteriuria [male:female-1:1, > 50% were 11-18 years of age group]. E. coli was predominant (86%) followed by K. pneumoniae (11%). Susceptibility of E. coli was highest against fosfomycin (100%) followed by carbapenems (90.7%) and nitrofurantoin (88.8%). ST131 (15.8%) and ST167 (10.5%) found as high-risk clones with the presence of plasmid [IncFIB (63.1%), IncFIA (52.6%)], and composite transposon [Tn2680 (46.6%)] in many isolates. Few isolates coharboured multiple beta-lactamases including blaNDM-5 (33.3%), blaOXA-1 (53.3%), blaCTX-M-15 (60%) and blaTEM-4 (60%). CONCLUSIONS: This study highlights horizontal transmission of resistance genes and plasmids in paediatric patients at community centers across the nation harbouring multidrug-resistant genes such as blaNDM-5 and blaCTX-M-15 associated with high-risk clones ST131 and ST167. The data is alarming and emphasizes the need for rapid identification of resistance markers to reduce the spread in community. To our knowledge, this is the first multicentric study targeting paediatric UTI patients from the community setting of India.

Resistance-associated mutations in HIV-1 among patients failing first-line antiretroviral therapy.

Thirty-five HIV-1 infected patients showing clinical and/or immunological failure to first line antiretroviral therapy (ART) according to WHO criteria were recruited from the ART center of Lok Nayak Hospital, New Delhi to detect the presence of resistance-mutations in reverse transcriptase (RT) and protease (PR) region of pol gene of HIV-1. Plasma viral load (PVL) was estimated. HIV-1 pol gene region encoding complete protease and reverse transcriptase (codons; 1-232 to 1-242) was reverse transcribed, followed by nested PCR. The PCR product was sequenced and analyzed. Plasma samples from 94.3% of patients with PVL >log(10) 3.0 c/mL could be amplified and analyzed. Virologic failure was detected in 65.7% of patients according to WHO criteria (PVL >log(10) 4.0). All patients were found to be infected with subtype C. One or more resistance-mutations were observed among 90.9% of study sequences. Nucleoside reverse transcriptase inhibitor (NRTI) resistance mutations were seen among all patients, with M184V and thymidine analogue mutations (TAM) being most frequently detected (75.6% and 72.7%, respectively). Nonnucleoside reverse transcriptase inhibitor (NNRTI) resistance-mutations were detected in 63.6% of sequences, of which Y181C/I (47.6%), K103N (33.3%) and G190S (28.6%) are the most common. None of the sequences showed major protease inhibitors (PIs) resistance mutation. High prevalence of NRTI and NNRTI drug resistance mutations among the study participants warrants the use of genotypic resistance testing to prevent accumulation of resistance mutations, which would limit future treatment options.

Polymicrobial growth in standard urine culture: Time to Act or Ignore?

Diagnosing Urinary Tract Infections (UTI) remains a clinical challenge. A monobacterial growth in standard urine culture is diagnostic while polymicrobial growth is usually considered as contaminants. However, in certain cases, true mixed infections may exist making it important to correctly identify the pathogens and streamline the therapy. Communication between the clinician and microbiologist is essential to establish the right diagnosis at right time. Here, we would like to share our experience about a polymicrobial UTI in a paediatric patient in which coordinated discussion between the clinical team and microbiologist was helpful for favourable outcome.

Azithromycin for Poorly Controlled Asthma in Children: A Randomized Controlled Trial.

BACKGROUND: Azithromycin has immunomodulatory actions, and its beneficial effects have been demonstrated in asthmatic adults. Data on children are limited. RESEARCH QUESTION: Does the addition of oral azithromycin to standard therapy in children with poorly controlled asthma improve asthma control compared with standard treatment alone? STUDY DESIGN AND METHODS: This open-label randomized controlled trial included children (5-15 years of age) with poorly controlled asthma defined by Asthma Control Test (ACT) and Childhood Asthma Control Test (CACT) score of ≤ 19. They were randomized to receive azithromycin (10 mg/kg) three times weekly for 3 months along with standard treatment or standard treatment alone. The primary outcome was the ACT and CACT scores at 3 months. Secondary outcomes were asthma control according to Global Initiative for Asthma (GINA) guidelines, the number of exacerbations, change in spirometry parameters, change in fractional exhaled nitric oxide (Feno) level, positive throat swab results, and side effects. RESULTS: The trial included 120 children (89 boys; 60 in each group). The mean ± SD age was 9.9 ± 3 years. The baseline parameters were similar between the groups. Mean ± SD ACT and CACT scores (available for 115 children) at 3 months of intervention were 21.71 ± 2.17 vs 18.33 ± 2.19 (P < .001) in the azithromycin and control groups, respectively. The numbers of children with well-controlled asthma according to GINA guidelines were 41 of 56 vs 10 of 56 in the azithromycin and control groups, respectively (P < .001). The median number of exacerbations requiring emergency visit and steroid use were fewer in the azithromycin group: 0 (interquartile range [IQR], 3) vs 1 [IQR, 6]; P < .001). No difference was found in Feno level, spirometry parameters, positive throat swab results, and adverse effects between the groups. INTERPRETATION: The use of azithromycin in children with poorly controlled asthma resulted in improved asthma control and reduced exacerbations. TRIAL REGISTRY: Clinical Trials Registry - India; No.: CTRI/2019/06/019727; URL: www.ctri.nic.in.

Intestinal Colonization Due to Carbapenem-Resistant Enterobacteriaceae Among Hematological Malignancy Patients in India: Prevalence and Molecular Charecterisation.

Faecal carriage of Carbapenem-resistant Enterobacteriaceae (CRE) is being observed as an important risk factor for bacteremia among patients with hematological malignancies. A prospective surveillance study was conducted among these patients to determine the gut colonization of CRE. Rectal/perianal swabs were collected to isolate CRE. Carbapenem resistance was detected by disk diffusion, modified-Hodge, Carba-NP test, and PCR for bla NDM-1, bla KPC, bla OXA-48, bla VIM, bla IMP genes. A total of 209 CRE isolates were identified from 151 patients. E. coli was the most common (83.2%) CRE identified, followed by Klebsiella spp. (9.6%). The majority of CRE were observed resistant to ertapenem (86%). bla NDM-1 was the most common gene (57.3%), followed by bla OXA-48 (37.8%). 26.8% isolates found to carry both bla NDM-1 and bla OXA-48 genes. CRE is increasingly observed to cause bacteremia among hematological malignancy patients due to increased colonization. Screening for gut CRE colonization is necessary to guide empirical therapy and apply infection control measures among these patients.

Clinical use of multiplex-PCR for the diagnosis of acute bacterial meningitis.

Background and Objectives: Prompt and accurate diagnosis of acute bacterial meningitis (ABM) is critical for patient management. We designed and evaluated two sets of multiplex-PCR assays for the simultaneous detection of six major etiologies of ABM i.e., Streptococcus pneumoniae, Haemophilus influenzae type b, and Neisseria meningitidis in one set and Listeria monocytogenes, Streptococcus agalactiae, and Escherichia coli in another set of multiplex-PCR in CSF of patients with suspected ABM. Methods: A total of 113 CSF specimens from patients of all ages having clinical features suggestive of meningitis were tested for bacteriological evidence by Gram's smear, culture, and our designed multiplex-PCR. Results: Multiplex-PCR assay performed excellently by increasing the overall detection rate by 6% when compared to culture as of total 113 samples tested, 17 (15%) were positive by multiplex-PCR whereas only 9% (10/113) were positive by culture. It detected the DNA in eight culture negative samples revealing the presence of S. pneumoniae in three and other possible bacterial pathogens in five of them. Our assay showed a DNA detection limit of 1 pg/µL. Compared to CSF culture, the sensitivity and specificity of the multiplex-PCR were 90% and 92.2%, respectively. Conclusion: This study accentuates the importance of multiplex-PCR assay that is efficiently fast and reliable for the diagnosis of acute bacterial meningitis that can substantially improve the diagnosis in culture negative cases, especially in patients who were previously started on antimicrobial therapy.

Genomic analysis of Fosfomycin resistance in multi-drug resistant uropathogens and comparison of in-vitro susceptibility methods uropathogens.

Background and Objectives: Urinary tract infection is one of the most common bacterial infections causing high morbidity and mortality. The alarming rise of multidrug-resistant uropathogens worldwide forced the clinician to rethink the old drugs like Fosfomycin for its therapeutic management. Our objective was to compare agar dilution, disc diffusion and E-test method for antimicrobial susceptibility testing of Fosfomycin against different drug-resistant uropathogens. Materials and Methods: Consecutive 181 uropathogens were tested for Fosfomycin susceptibility using agar dilution, disc diffusion and E-test. Results were interpreted using Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints. Whole genome sequencing analysis was done on the 4 XDR/PDR Fosfomycin resistant Klebsiella pneumoniae isolates. Results: Escherichia coli was found as the most common (62.4%) uropathogen followed by Klebsiella pneumoniae (21%). Considering agar dilution as the gold standard, 6.1% of isolates were resistant to Fosfomycin. Following CLSI breakpoints, the susceptibility of Escherichia coli, Klebsiella pneumoniae, other Enterobacterales and Pseudomonas aeruginosa were 92.9%, 92.1%, 100%, 100%; whereas using EUCAST breakpoints the susceptibility rates were 85.7%, 86.9%, 92.9%, and 100%, respectively. The essential agreement, categorical agreement, major error, and very major error for E-test/disc diffusion for all the organisms were 91.2%/Not Applicable, 95%/93.9%, 1.8%/4.7%, 9.1%/9.1%, respectively. Whole-genome sequencing showed mutation UhpT gene as well as the presence of plasmid-mediated fosA5 or fosA6 genes conferring Fosfomycin resistance. Conclusion: This result supports very low resistance of Enterobacterales against Fosfomycin; hence should be considered a valuable option to treat multidrug-resistant uropathogens. Disc diffusion was observed to be a convenient method for Fosfomycin susceptibility testing compared to agar dilution.

Analysis of colistin resistance in carbapenem-resistant Enterobacterales and XDR Klebsiella pneumoniae.

INTRODUCTION: Increasing occurrence of infections caused by multidrug-resistant Gram-negative bacteria resulted in colistin being the last agent for treatment. Apart from plasmid-mediated mcr genes, mutations involving several genes like mgrB, phoP/phoQ, pmrA, pmrB, pmrC, and crrABC genes, are leading causes of colistin resistance. Four colistin susceptibility testing methods were compared against broth microdilution (BMD) and determined the presence of the mcr1-5 gene. METHODOLOGY: A total of 100 carbapenem-resistant Enterobacterales isolates were tested for colistin susceptibility by commercial broth microdilution (cBMD), E-test, VITEK-2, and rapid polymyxin NP assay (RPNP) and compared with BMD. The presence of the mcr1-5 gene was determined by modified RPNP and PCR. Two non-mcr colistin-resistant XDR isolates were subjected to whole-genome sequencing using Illumina MiSeq sequencing platform. RESULTS: Among 100 carbapenem-resistant Enterobacterales isolates, 15% were resistant to colistin. Essential agreement, categorical agreement, major error, and very major error for cBMD/E-test/VITEK-2/RPNP were 96%/73%/82%/NA; 99%/86%/88%/91%, 1.2%/9.4%/11.8%/8.2% and 0%/40%/13.3%/13.3%, respectively. Only one Klebsiella pneumoniae isolate harbored the mcr-1 gene, observed by both methods. Whole-genome sequencing of two non-mcr XDR Klebsiella pneumoniae showed multiple mutations in 10 genes responsible for lipopolysaccharide biosynthesis. CONCLUSIONS: The performance of cBMD was excellent, whereas the E-test was unacceptable. VITEK-2 and RPNP performed better but remained unreliable due to high error rates. Multiple mutations in the target proteins involving lipopolysaccharide formation, modification, and regulation were seen, resulting in colistin resistance.