Apurba Sankar Sastry

Coryneforms other than Corynebacterium diphtheriae are often ignored when isolated from clinical laboratories as in most instances they represent the normal commensals of skin. Corynebacterium jeikeium was initially considered only as commensal, later it was identified as the causative agent for severe sepsis in immunocompromised patients. Here, we present a case of meningoencephalitis caused by Corynebacterium jeikeium in a 30 year old adult male with HIV and tuberculosis co-infection. Serial cerebrospinal fluid from external ventricular drainage had grown Corynebacterium jeikeium which was identified by automated MALDI-TOF system which aided in the timely diagnosis and prompt management of the patient. Keywords: Corynebacterium jeikeium, Meningoencephalitis, HIV tuberculosis co-infection, External ventricular drainage.

Melioidosis, caused by a non-fermenting gram negative bacilli Burkholderia pseudomallei, can mimic a variety of diseases due to its diverse clinical presentation. The incidence of cardiac involvement in melioidosis is less than 1%. We report a rare case of melioidosis in a 65 year old male with chronic kidney disease who presented with fever and pericardial effusion which was misdiagnosed and treated as tuberculous pericardial effusion. Later, on isolation of Burkholderia pseudomallei from paired blood culture samples, pericardial fluid and also from pleural fluid confirmed the diagnosis of disseminated melioidosis. The patient was treated with intravenous ceftazidime after which clinical improvement was observed. Cardiac melioidosis should always be considered in the differential diagnosis of tuberculous pericardial effusion and it should be ruled out before the start of anti-tubercular treatment. This will prevent unnecessary exposure to anti-tubercular drugs and also aids to start early treatment for melioidosis thereby reducing the mortality. Keywords: Melioidosis, Pericardial effusion, Burkholderia pseudomallei.

With ascending trend of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin resistant Enterococci (VRE) prevalence in community as well as hospital settings, use linezolid has proportionately increased because of its high oral bioavailability and good clinical cure rate. However, cases of linezolid resistance have also come up in certain strains of Enterococcus and methicillin-resistant Staphylococcus aureus (MRSA), which can be attributed to nosocomial transmission and extensive usage of the antibiotic. This alarming situation leaves the clinician with limited treatment options. Such a condition requires, reduction of inadvertent use of linezolid and following appropriate infection-control measures to contain the spread of linezolid-resistant pathogens. Here, we present a rare case of vancomycin sensitive and linezolid resistant Enterococcus faecium with minimum inhibitory concentration (MIC) of linezolid being >256 mg/mL in a sepsis patient. Keywords: Enterococcus faecium, Vancomycin sensitive, Linezolid resistant, Disc diffusion, MIC.

Aim: To determine the appropriateness of blood volume in automated blood culture bottles of the BACT/ALERT 3D system, its effect on isolation rate and time to positivity of pathogens. Materials and Methods: The study was carried out in a tertiary care hospital in South India from 1st March 2018 to 31st August 2018. Automated blood culture bottles sent to Microbiology laboratory for blood culture were included in the study. The bottles were weighted by electronic weighing balance. The filled blood culture bottles received at microbiology laboratory were re-weighed and was categorized into appropriately filled and inappropriately filled bottles. Frequency of appropriately filled bottles and inappropriately filled bottles was expressed in percentage. Result: A total of 8740 blood culture bottles were included in the study, out of which the blood volume was found to be suboptimum in 3978 bottles (45.5%), optimum in 3498 bottles (40%) and overfilled in 1264 bottles (14.5%). There was an increase in the number of blood culture bottles with optimum blood volume from 35.1% in March to 58.12% in August. The average TTP for true pathogens was found to be 16.72 hrs. with optimum blood volume, 17 hrs. with overfilled blood volume and 21.5 hrs. with sub-optimum blood volume. The isolation rate for true pathogens was found to be 88.62% with optimum blood volume, 86.43% with overfilled blood volume and 70.01% with sub-optimum. The false positive rate was found to be 4.1% with overfilled blood volume, 1.6%with sub-optimum and 1.4%with optimum blood volume. Conclusion: Through this study, the correlation between the blood volume with the isolation rate, time to positivity and false positivity of blood culture isolates was established. Keywords: Blood culture, Blood volume, BACT/ALERT 3D, Time to positivity, Isolation rate.

Recommendations by manufacturers depict that blood culture bottles are to be loaded into the automated machines as soon as possible after the blood collection. But it has been noticed that in peripheral set-ups where round the clock laboratory facility is not available or which are located far from the reference labs, or even in the tertiary care centres, delay occurs prior to the bottle loading into the instruments. In our study, we have compared the effect of pre-incubating the blood culture bottles at various temperatures like 4°C, room temperature and 37°C for various holding times, such as 2, 6, 12 and 24 hours simulating the delay in transport time in BACTEC plus Aerobic and BACTALERT FA plus systems in a tertiary care set up. We included five recent clinical isolates of different microorganisms in our study, such as Staphylococcus aurous, Streptococcus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. Standard inoculum was prepared for each organism and 3 ml of it was added with 10 ml of citrated human blood and then inoculated into blood culture vial (BACTALERT FA plus and BACTEC Plus). Organism recovery rate, time to detection and rates of false-negativity from both the instruments were evaluated by using seeded blood culture vial and controls with delayed entry. Performance wise analysis showed that the overall isolation rate of the organisms from BACTEC bottles was higher compared to BACTALERT. Also BACTEC showed less average TTD compared to BACTALERT for Pseudomonas aeruginosa, Streptococcus and candida albicans but for E. coli and S. aureus BACTALERT showed earlier detection. To conclude, storage of the inoculated bottles at room temperature gave optimal recovery of the organisms for both BACTEC and BACTALERT systems, if delayed entry is inevitable. Keyword: Delayed vial entry effect on recovery of microorganisms.