ABSTRACT
Background & objectives: Acinetobacter baumannii is an opportunistic pathogen responsible for causing nosocomial infections. A. baumannii develops resistance to various antimicrobial agents including carbapenems, thereby complicating the treatment. This study was performed to characterize the isolates for the presence of various ?-lactamases encoding genes and to type the isolates to compare our clones with the existing international clones across five centres in India. Methods: A total 75 non-repetitive clinical isolates of A. baumannii from five different centres were included in this study. All the isolates were confirmed as A. baumannii by bl aOXA-51-likePCR. Multiplex PCR was performed to identify the presence of extended spectrum ?-lactamases (ESBL) and carbapenemases. Multilocus sequence typing was performed to find the sequence type (ST) of the isolates. e-BURST analysis was done to assign each ST into respective clonal complex. Results: blaOXA-51-likewas present in all the 75 isolates. The predominant Class D carbapenemase was blaOXA-23-likefollowed by Class B carbapenemase, blaNDM-like. Class A carbapenemase was not observed. blaPER-likewas the predominant extended spectrum ?-lactamase. ST-848, ST-451 and ST-195 were the most common STs. Eight-novel STs were identified. e-BURST analysis showed that the 75 A. baumannii isolates were clustered into seven clonal complexes and four singletons, of which, clonal complex 208 was the largest. Interpretation & conclusions: Most of the isolates were grouped under clonal complex 208 which belongs to the international clonal lineage 2. High occurrence of ST-848 carrying blaOXA-23-likegene suggested that ST-848 could be an emerging lineage spreading carbapenem resistance in India.
ABSTRACT
Background: Pseudomonas aeruginosa is one of the most common opportunistic pathogens that cause severe infections in humans. The burden of carbapenem resistance is particularly high and is on the rise. Very little information is available on the molecular mechanisms and its clonal types of carbapenem-resistant P. aeruginosa seen in Indian hospitals. This study was undertaken to monitor the ?-lactamase profile and to investigate the genetic relatedness of the carbapenemase-producing (CP) P. aeruginosa collected across different hospitals from India. Materials and Methods: A total of 507 non-duplicate, carbapenem-resistant P. aeruginosa isolated from various clinical specimens collected during 2014–2017 across seven Indian hospitals were included. Conventional multiplex polymerase chain reaction for the genes encoding beta-lactamases such as extended-spectrum beta-lactamase (ESBL) and carbapenemase were screened. A subset of isolates (n = 133) of CP P. aeruginosa were genotyped by multilocus sequence typing (MLST) scheme. Results: Of the total 507 isolates, 15%, 40% and 20% were positive for genes encoding ESBLs, carbapenemases and ESBLs + carbapenemases, respectively, whilst 25% were negative for the ?-lactamases screened. Amongst the ESBL genes, blaVEB is the most predominant, followed by blaPER and blaTEM, whilst blaVIM and blaNDM were the most predominant carbapenemases seen. However, regional differences were noted in the ?-lactamases profile across the study sites. Genotyping by MLST revealed 54 different sequence types (STs). The most common are ST357, ST235, ST233 and ST244. Six clonal complexes were found (CC357, CC235, CC244, CC1047, CC664 and CC308). About 24% of total STs are of novel types and these were found to emerge from the high-risk clones. Conclusion: This is the first large study from India to report the baseline data on the molecular resistance mechanisms and its association with genetic relatedness of CP P. aeruginosa circulating in Indian hospitals. blaVIM- and blaNDM-producing P. aeruginosa is the most prevalent carbapenemase seen in India. Majority of the isolates belongs to the high-risk international clones ST235, ST357 and ST664 which is a concern.
ABSTRACT
We report a case of Shigella flexneri serotype‑2 causing bacteremia in an elderly gentleman with uncontrolled diabetes mellitus, who had no other apparent risk factors. Antibiotic susceptibility testing revealed that the organism was a multidrug resistant extended spectrum beta‑lactamase producing strain, which was confirmed by molecular characterization. This rare case alerts both the clinician and microbiologist to a previously unaddressed risk factor of Shigella spp. causing bacteremia, as well as emerging resistant strains that are on the rise in immunocompromised patients.
ABSTRACT
Background. Disseminated histoplasmosis is a chronic granulomatous disease caused by the dimorphic fungus, Histoplasma capsulatum. Clinical presentation can vary from the acute pulmonary to the chronic disseminated form. In India, disseminated histoplasmosis often presents with pyrexia of unknown origin with a presentation similar to ‘disseminated tuberculosis’ involving the adrenal glands and bone marrow. Due to rarity of the disease, data are lacking regarding its clinical presentation and outcome among immunocompromised and immunocompetent patients. Methods. During January 2000 to December 2010, we identified 37 patients of disseminated histoplasmosis and attempted to characterize the differences between immunocompromised and immunocompetent patients. Demographic characteristics, clinical presentation, risk factors, laboratory findings, diagnostic yield, treatment received and prognosis were noted and compared between the two groups. Results. Eleven of 37 patients with disseminated histoplasmosis were immunocompromised and 26 were immunocompetent. Comparison of their clinical features showed a higher frequency of skin lesions in the immunocompromised compared to the immunocompetent group (54.5% v. 11.5%). Pancytopenia and anaemia were more common among the immunocompromised (81.8%) compared to the immunocompetent (46.2%) group. In the immunocompromised patients, the diagnosis was made most often by bone marrow aspirate and culture (72.7%) compared to the immunocompromised group where the diagnosis was most often obtained by adrenal gland biopsy and fungal cultures (57.7%). The cure rate was significantly higher in the immunocompetent group (73% v. 45%). Conclusion. The clinical presentation and outcome of patients with disseminated histoplasmosis differs among immunocompromised and immunocompetent patients.