Metallo-β-lactamase producing nonfermentative gram-negative bacteria:An increasing clinical threat among hospitalized patients

Objective:To detect and evaluate the various methods for metallo-β-lactamases(MBL) production in Pseudomonas aeruginosa(P.aeruginosa) and Acinetobacter species.Methods:A total of 109 P.aeruginosa and 85 Acinetobacter species were screened for imipenem resistance by Kirby- Bauer disc diffusion methods.Detection of MBL production was(lone by imipenem-EDTA combined disc test,double disc synerygy test(DDST) and imipenem-EDTA MBL E test.Results: A total of 63(57.8%) strains of P.aeruginosa and 46(54.1%) strains of Acinetobacter spp.were found to be resistant to imipenem.Of the 63 imipenem resistant P.aeruginosa tested for MBL production.44(69.89;) were found to be positive and among 46 imipenem resistant Acinetobacter. 19(41.3%) were shown to be the MBL producers.Conclusions:Imipenem-EDTA combined disc test and MBL E test are equally effective for MBL detection in both P.aeruginosa and Acinetobacter spp.,but given the cost-constraints,combined disc can be used as a convenient screening method in the clinical microbiology laboratory.

Outbreak of Salmonella Typhi enteric fever in sub-urban area of North India:A public health perspective

Outbreaks of enteric fever are a major health concern not only due to significant human morbidity and mortality but also fear of spread of multidrug resistant strains.We report an outbreak of enteric fever caused by Salmonella enterica serotype Typhi in a suburban area,in city Chandigarh of North India.Twenty-seven strains of S.typhi were isolated from blood cultures over a period of two weeks with 18 of these 27 patients residing in the same area.Maximum cases were in the age group 5-14 years(10 patients,55.5%) while 4(22.2%) cases were children under 5 years.All the strains showed similar resistogram being resistant to ampicillin and nalidixic acid,intermediate to ciprofloxacin and sensitive to chloramphenicol,ceftriaxone,cefotaxime,cotrimoxazole and azithromycin on disc diffusion testing.Minimum inhibitory concentration of ciprofloxacin was determined by agar dilution method and was found to be raised(≥2μg/mL).This nalidixic acid resistant S.typhi outbreak report warrants the necessity of implementing stringent sanitation practices in public health interest.

Linezolid resistant Staphylococcus haemolyticus:First case report from India

Linezolid is being increasingly used in the treatment of infections with gram-positive organisms especially methicillin resistant Staphylococcal isolates.Though resistance to this antimicrobial is emerging but it is extremely rare.Here we document first case of linezolid resistant Staphylococcus haemolyticus(S.haemolyticus) from India.This organism was isolated from pus oozing from a postsurgical site in 61 year old male hailing from an adjoining state of Haryana.

Salmonella-Salmonellosis-Rare presentations of a common pathogen

Salmonella are most commonly associated with gastroenteritis and enteric fever in humans. Occasionally,dissemination of bacilli throughout the body results in establishment of localized foci of persistent infection especially in patients with debilitating diseases and immunosuppressive states.Infection at various aberrant sites due to Salmonella has been reported relatively seldom.It has perfected the art of intracellular survival in niches from where they can cause myriad of effects.Six cases with Salmonella infection at unusual sites without any preexisting or underlying disease diagnosed over a period of two years are presented here.Salmonella etiology was not suspected in these patients and the diagnosis was made microbiologically only after culture isolation.

What the Internist Should Know about Thrombotic Microangiopathies

Thrombotic microangiopathy (TMA) is a group of diseases that are life-threatening and can lead to end organ damage (EOD) due to ischemia caused by microthrombi in capillaries and arterioles. TMAs can affect any organ system but usually affect the kidney, intestines, and nervous system. The triad of TMA is Coombs-negative hemolytic anemia with schistocytes seen on peripheral smear, thrombocytopenia (platelets under 150,000 or a decrease of 25% or more from baseline), and evidence of ischemic EOD. Primary TMAs include Thrombotic Thrombocytopenic Purpura (TTP), Hemolytic Uremic Syndrome (HUS) and atypical HUS (aHUS). Pathophysiologically, all of these diseases are caused by aggregation of von Willebrand Factor (vWF) multimers, via different mechanisms, which eventually leads to thrombus formation. TTP and aHUS benefit from plasma exchange (PEX), whereas HUS is treated symptomatically. Urgent recognition with timely treatment is crucial to managing these potentially life-threatening conditions.

Post-traumatic thrombotic microangiopathy: What trauma surgeons need to know?

Thrombotic microangiopathy(TMA)is characterized by systemic microvascular thrombosis,target organ injury,anemia and thrombocytopenia.Thrombotic thrombocytopenic purpura,atypical hemolytic uremic syndrome and Shiga toxin E-coli-related hemolytic uremic syndrome are the three common forms of TMAs.Traditionally,TMA is encountered during pregnancy/postpartum period,malignant hypertension,systemic infections,malignancies,autoimmune disorders,etc.Recently,the patients presenting with trauma have been reported to suffer from TMA.TMA carries a high morbidity and mortality,and demands a prompt recognition and early intervention to limit the target organ injury.Because trauma surgeons are the first line of defense for patients presenting with trauma,the prompt recognition of TMA for these experts is critically important.Early treatment of post-traumatic TMA can help improve the patient outcomes,if the diagnosis is made early.The treatment of TMA is also different from acute blood loss anemia namely in that plasmapheresis is recommended rather than platelet transfusion.This article familiarizes trauma surgeons with TMA encountered in the context of trauma.Besides,it provides a simplified approach to establishing the diagnosis of TMA.Because trauma patients can require multiple transfusions,the development of disseminated intravascular coagulation must be considered.Therefore,the article also provides different features of disseminated intravascular coagulation and TMA.Finally,the article suggests practical points that can be readily applied to the management of these patients.