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Carbapenemases are the enzymes that can hydrolyze carbapenems and other β-lactam antibiotics. These enzymes confer resistance to multiple antibiotics and act as a stumbling block in the treatment of infections caused by gram-negative bacteria. Therefore, rapid and specific detection of these enzymes is crucial for deciding the course of treatment and better clinical outcomes.This study was conducted to compare various phenotypic and PCR based methods for the detection of carbapenemases in carbapenem- and colistin-resistant Klebsiella pneumoniae. One hundred clinical isolates of extensively resistant Klebsiella pneumoniae were included in the study. Phenotypic detection for carbapenemases was performed by Rapidec® Carba NP (Biomerieux), modified carbapenem inactivation method (mCIM), imipenem-ethylenediaminetetraacetic acid disk synergy (EDS), double disk synergy test using mercaptopropionic acid (DDST-MPA), and combined disk method (CD) and for colistin by microbroth dilution method. Genotypic detection for carbapenemases and colistin resistance was performed by targeted PCR.The sensitivity of Carba NP test and mCIM were positive in 95% and 96% respectively and specificity was 100% for both methods. The sensitivity of EDS, DDST-MPA, and CD were 55.6%, 88.9% and 54.5% respectively. Among the carbapenem resistance genes, blaOXA-48 (82%) genes were the most prevalent. Among metallo-beta lactamases, blaVIM (56%) was most common followed by blaNDM (54%) and blaIMP (20%). The mcr-1 gene for colistin resistance was not detected in any isolate.Among the five phenotypic assays analyzed, the mCIM is the most simple, inexpensive, accurate and reproducible method for carbapenemase detection in Klebsiella pneumoniae. The DDST-MPA test provides the best sensitivity for the detection of carbapenemases, although specificity is low. These tests, when applied in a clinical laboratory and assessed by the microbiologist, can help in guiding the course of treatment.

Haemophilus influenzae (H. influenzae) causes invasive disease like bacteremia which is rarely diagnosed. We conducted this retrospective study of H. influenzae bacteremia diagnosed between January 2016 and December 2020. Nineteen patients were identified. Majority were children ≤5 years of age (84.2%), inpatients (89.5%), males (78.9%) and admitted in ICUs (26.6%). The most common underlying primary diagnosis was malignancy. These isolates were most susceptible to carbapenems (100%) followed by cefotaxime (83.3%) and ampicillin (82.4%). The overall mortality rate was 33.3%. Increased mortality resulted in those admitted in ICUs with H. influenzae bacteremia episode along with polymicrobial/co-isolates infection.

Background Stenotrophomonas maltophilia causes opportunistic infections in immunocompromised and patients in intensive care units (ICUs). An outbreak of S. maltophilia in ICU is described which highlights the importance of the risk of infection from contaminated medical devices and suction fluids in ventilated patients. Methods The investigation of the outbreak was carried out. Environmental sampling was done. This was followed by MALDI-TOF MS typing and recA gene-based-phylogeny. Results In February, S. maltophilia was reported from the central line blood of six patients from ICU within a span of two weeks. The peripheral line blood cultures were sterile in all patients. Relevant environmental sampling of the high-touch surface and fluids revealed S. maltophilia strains in normal saline used for suction and in the inspiratory circuit of two patients. The isolated strains from patients and environment (inspiratory fluid) showed a minimum of 95.41% recA gene sequence identity between each other. Strict cleaning and disinfection procedures were followed. Continuous surveillance was done and no further case of S. maltophilia was detected. Timely diagnosis and removal of central line prevented development of central-line associated blood stream infection. Conclusion This outbreak report illustrates that environmental sources like suction fluid and normal saline could be the source of S. maltophilia in ICU patients.

Objective Several studies have demonstrated a shift in the spectrum of infective endocarditis (IE) in the developed world. We aimed to investigate whether demographic and microbiologic characteristics of IE have changed in India. Design A retrospective analysis of patients with in north India between 2010 and 2020. Methods The clinical and laboratory profiles of 199 IE admitted to an academic hospital patients who met the modified Duke criteria for definite IE were analysed. Results The mean age was 34 years, and 84% were males. The main predisposing conditions were injection drug use (IDU) (n = 71, 35.7%), congenital heart disease (n = 46, 21.6%), rheumatic heart disease (n = 25, 12.5%), and prosthetic device (n = 19, 9.5%). 17.1% of patients developed IE without identified predispositions. Among 64.3% culture-positive cases, the most prevalent causative pathogens were Staphylococcus aureus (46.1%), viridans streptococci (7.0%), enterococci (6.0%), coagulase-negative staphylococci (5.5%), gram negative bacilli (5.5%), polymicrobial (5.5%), and Candida (1.0%). The tricuspid (30.3%), mitral (25.6%), and aortic (21.6%) valves were the most common sites of infection, and 60.3% had large vegetations (>10 mm). Systemic embolization occurred in 55.3% of patients at presentation. Cardiac surgery was required for 13.1%. In-hospital mortality was 17.1% and was associated with prosthetic devices (p-value, 0.001), baseline leucocytosis (p-value, 0.036) or acute kidney injury (p-value, 0.001), and a microbial etiology of gram negative bacilli or enterococci (p-value, 0.005). Conclusion IDU is now the most important predisposition for IE in India, and S. aureus has become the leading cause of native valve endocarditis with or without IDU.

Hospital-acquired infections are a known menace to the primary disease, for which a patient is admitted. These infections are twenty times more common in developing countries than in the developed ones. Surveillance for colonised patients can be passive or active process. In many hospitals, active surveillance culture for certain sentinel organisms followed by contact precautions for the same is an important part of infection control policy. Specific measures can be taken on early detection of multidrug-resistant organism, allowing prevention of widespread transmission in hospitals. Cultures are the most conventional and economical microbiological method of detection. The cost of active surveillance is a major challenge, especially for developing nations. These nations lack basic infrastructure and have logistic issues. The guidelines regarding this are not very clearly delineated for developing countries. Each hospital has its own challenges and the process is to be tailor-made accordingly. The following review delineates the various aspects of active surveillance for the colonisation of various organisms and the advantages and disadvantages of the same.

Bacteroides nordii, is an understudied member of the pathogenic B. fragilis group which comprises several multidrug-resistant (MDR) strains. Thus, it is of great interest to study the genome biology of Bacteroides nordii. However, no detailed study is available that characterized B. nordii at the genetic level and explored its role as a potential pathogen. We isolated an MDR strain viz., B. nordii PGMM4098 from the pus sample and subjected it to whole genome sequencing using Illumina technology. The draft genome was de-novo assembled and annotated, followed by comprehensive comparative genomics analyses using the publicly available genome dataset of B. nordii. The pan-genome analysis revealed the open nature of B. nordii, indicating the continuous accumulation of novel genes in non-core components leading to the emergence of new strains of this species. The thirteen antimicrobial resistance (AMR) genes identified in the genomes of all B. nordii strains were part of the non-core component of the pan-genome. Of these, four AMR genes, nimE, aadS, mef(En2), and ermB/F/G were found to be acquired via the process of horizontal gene transfer (HGT) from anaerobic Bacteroidetes. Importantly, the nimE gene conferring metronidazole resistance was found to be present only in B. nordii PGMM4098, which harbors five other AMR genes encoded in its genome. Of these, nimE (metronidazole resistance), ermB/F/G (macrolide-lincosamide-streptogramin B resistance), and cfxA2/A3 (class A β-lactam resistance) genes were further validated using targeted polymerase chain reaction assay. Notably, these three genes were also found to be under the operation of positive selective pressure suggesting the diversification of these genes, which might lead to the emergence of new MDR strains of B. nordii in the near future. Our study reported and characterized the genome of the first MDR strain of B. nordii and revealed the AMR evolution in this species using a comprehensive comparative genomics approach.

To date, antimicrobial susceptibility testing (AST) in anaerobes is highly disarrayed. The testing is not routinely performed in many laboratories to direct appropriate antimicrobial therapy, and literature on AST remains scarce. This review aims to present the current methods employed for the AST of anaerobic bacteria both in routine and research. Anaerobes are potential human pathogens and predominate the human microbiota. Despite their significant role in human health and disease, they are not paid enough heed. The educated experience-based treatment has often been instituted with anaerobic infections due to the challenging AST and relatively predictable patterns of antimicrobial resistance (AMR). However, the AMR in anaerobes remains no more predictable, especially in Gram-negative anaerobes like Bacteroides spp., where multi-drug resistance is also emerging. The changing antibiograms and the emergence of resistance determinants in anaerobes necessitate routine AST, periodic monitoring, and literature review of these organisms. The present scenario dictates to limit the empirical management of anaerobic infections and encourage consistent AST practice in routine by employing economical, faster, and more pragmatic approaches, especially in tertiary care setups that cater to a vast patient population and are held accountable for producing accurate clinical and surveillance data. The article may provide a broad perspective on the topic and different AST solutions.

Bevacizumab, a recombinant humanized monoclonal antibody to inhibit tumour angiogenesis, is available for off-label use for treating choroidal neovascularization. Outbreaks have been reported after use of this drug, either because of contamination during manufacturing or the practice of multiple doses being administered from a single vial to different patients. In our institute we investigated one endophthalmitis outbreak following intravitreal injection of bevacizumab, rapidly identified the Stenotrophomonas maltophilia as the causative agent, and established the contaminated bevacizumab vial as the source using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF-MS) typing. The study emphasizes the need for early diagnosis of the source and pathogen for appropriate control measures.

To compare the performance of agar dilution and broth microdilution by commercial and in-house prepared plates for the Bacteroides fragilis group. The cost analysis was performed to demonstrate that in-house prepared BMD plates were a suitable alternative to agar dilution given the high cost and low feasibility of incorporating commercial BMD plates in routine, particularly in the tertiary care institutes of many low- and middle-income countries.Thirty B. fragilis group isolates were tested against six antibiotics, frequently used as empirical therapy for anaerobic infections including metronidazole, clindamycin, imipenem, piperacillin-tazobactam, cefoxitin, and chloramphenicol. The running consumable expenditure for all methodologies was calculated.The results demonstrated essential and categorical agreement of90% for all antibiotics except cefoxitin, which showed90% categorical agreement. No major or very major errors were observed. We observed a high agreement and strong concordance for MIC values between both methods and inter-rate reliability of0.9 by Cohen's kappa analysis, indicating almost perfect agreement between both methods using either of the plates. In contrast to agar dilution, a 20.5 fold cost reduction was seen in BMD using in-house plates and a 5.8 fold reduction using commercial plates to test a single isolate. However, when testing 30 isolates concurrently the cost significantly increased for commercial BMD plates by 8.4 folds, and only 1.03 fold cost reduction was seen with in-house BMD plates.BMD gives comparable results to agar dilution and can be considered a method of choice to test a small number of samples. The technique is an economical option when plates are standardized in-house and could be employed for susceptibility testing of the B. fragilis group.

Legionella pneumophila is one of the important pathogen responsible for community –acquired pneumonia attributing for 1-5% of cases. Since early and accurate therapy reduces mortality, rapid and reliable diagnostic methods are needed. A total of 134 samples of blood, urine and respiratory tract fluids were collected. Blood was tested for IgG, IgM and IgA antibodies using commercially available kits. A total of 8 (6%) samples were found to be positive for L. pneumophila by quantitative reverse transcription polymerase chain reaction (qRT-PCR), compared to conventional PCR where 6 (4.4%) samples were positive. Serology was positive in a total of 32 (23%) cases though only 3 (2.2%) of the PCR-positive cases were positive by serology as well. These results suggest that real-time PCR can detect Legionella infection early in the course of the disease before serological response develops.

Brain abscess remains a life-threatening condition. Here, we are reporting a case of brain abscess due to Bacteroides thetaiotaomicron in a previously known case of recurrent otitis media. A 15 years old boy with a history of recurrent otitis media presented with the complaints of right otalgia, headache and fever. Computed Tomography (CT) brain and neck revealed fluid filled right middle ear cavity with bony destruction along the inner cortex of right temporal bone. The abscess was drained and culture showed growth of Bacteroides thetaiotaomicron. This report illustrates the importance of MALDI-TOF MS in the species level identification of anaerobes thereby facilitating the selection of appropriate and prompt adjuvant antibiotic therapy. This timely identification thus led to a favourable outcome in an era of increasing antimicrobial resistance.

Brain abscess remains a life-threatening condition. Here, we are reporting a case of brain abscess due to Fusobacterium nucleatum in a previously known case of Ebstein anomaly. A 44-year-old male presented with the complaints of headache, and fever. Cerebral imaging revealed parieto-occipital (PO) abscess. The abscess was drained and culture showed growth of Fusobacterium nucleatum. This report illustrates the importance of considering anaerobes as the cause of brain abscess, underscores the usefulness of MALDI, which facilitated the selection of appropriate and prompt adjuvant antibiotic therapy and a favourable outcome.