Search

Introduction: Blood cultures play an important role in the early diagnosis of sepsis and its management. Early detection of pathogens in Blood Stream Infections (BSI) and their Antimicrobial Susceptibility Testing (AST) pattern, plays a vital role in the diagnosis of sepsis and is important for guidance of appropriate therapy. Aim: To evaluate the accuracy of shortly incubated blood cultures in comparison with standard method for an early Identification (ID) and AST. Materials and Methods: This was a prospective observational study undertaken from July 2015 to June 2016 at Nizam’s Institute of Medical Sciences, Hyderabad, Telangana, India. The blood cultures were loaded in the BacT/Alert system. A total of 92 patients with two sets of blood cultures that flagged positive within 24 hours of collection were included in the study. Grams stain and subcultures of the broths were done. The culture plates were examined after four hours and then at hourly intervals for the presence of growth. Once the growth was sufficient it was processed immediately for ID and AST by Vitek 2C. Incubation of the plates was continued for the rest of the 24 hours at 37oC and was processed again. The mean time for detection were compared between short and standard cultures. Results: Gram negative pathogens were the predominant organisms isolated in 82/92 (89.1%) followed by gram positive in 10/92 (10.9%). The short and standard cultures had comparable results with respect to ID of the isolates. But, the AST results were comparable only in 88/92 (95.6%) patients. Of the remaining four patients, the AST showed Very Major Error (VME) in 3 (3.3%) patients and Major Error (ME) in 1 (1.08%) patient. Conclusion: Short incubation of cultures enabled earliest ID and AST of the isolates from blood cultures than standard incubation.

Introduction: Non-tuberculous Mycobacteria (NTM) pulmonary disease is often unrecognised or misdiagnosed as Mycobacterium tuberculosis (MTB), Multi-Drug Resistant Tuberculosis (MDRTB), because of similar clinical presentation in counties with high burden of Tuberculosis (TB) including India. In India due to lack of awareness among clinicians and lack of laboratory facilities to diagnose these infections, its prevalence is largely unknown. Aim: To evaluate the efficacy of identification of NTM species by Matrix Assisted Laser Desorption Ionisation Time of Flight (MALDI-TOF) and Heat Shock Protein (hSP65) gene sequencing and to determine their Antimicrobial Susceptibility Testing (AST). Materials and Methods: All the clinical specimens from pulmonary and extra-pulmonary TB suspects at Nizam’s Institute of Medical Sciences, Hyderabad, Telangana, India, over a period of one year i.e., from June 2017 to May 2018 were included in the study. The specimens were subjected to microscopy, culture and GeneXpert. The NTMs isolated in the culture were further characterised genotypically by MALDI-TOF and hsp65 gene sequencing. The identified NTM isolates were subjected to AST. All the methods were followed as per the standard protocols. Data was analysed using SPSS 25. Results: A total of 1085 samples were processed out of which Mycobacteria was detected in 201 cases (18.5%). Among the culture positives, MTB complex was detected in 146 cases (13.5%) and NTM in 55 (5.06%). Mycobacterium abscessus was the predominant isolate. The most common co-morbidities were bronchiectasis and Chronic Obstructive Pulmonary Disease (COPD). Linezolid, clarithromycin, moxifloxacin and amikacin showed high sensitivity. Conclusion: Molecular assay helps in rapid identification which can lead to targeted therapy and can thus combat antimicrobial resistance. The MALDI-TOF and hsp65 gene sequencing also offers quick results at a low cost and is easy to perform hence it can be considered as an alternate diagnostic tool for identification.

Introduction: Postoperative infections in orthopaedic implants is a major concerning factor. It can lead to the failure of implants and in severe cases can even lead to amputation and mortality. Total joint replacements and fracture fixations do help by reducing the agony of many patients but postoperative infections are a detrimental complication. It is an economic disaster for hospitals that treat large number of these patients therefore identification of risk factors, common pathogens involved, early initiation and prompt use of empirical therapy is necessary to prevent implant failures and also collection of deep tissue samples improves the diagnostic reliability and microbiological yield of implant related infections. Hence, appropriate collection of specimens is a key factor for early diagnosis and differentiating colonisers from true pathogens. Aim: To evaluate the rate of implant related infections, sensitivity of Gram’s stain and its accuracy in tissue samples over wound swabs and also to determine the trends in the antibiogram. Materials and Methods: A retrospective analysis was performed from the samples (tissues and wound swabs) received to the Department of Microbiology from October 1st 2017-October 30th 2018 (a period of one year) in patients with orthopaedic implants. Identification and susceptibility patterns of the bacterial pathogens were identified by the automated Vitek 2 compact system (biomeriux). The data was analysed in terms of frequency and percentage. Results: A total of 141 cases were analysed out of which 45.3% (64/141) were tissue samples and 54.6% (77/141) were wound swabs. Culture positivity observed in tissues was 43.7% (28/64), in wound swabs 50.6% (39/77) and mixed infections were observed in 7.14% (2/28) of tissues and 5.12% (2/39) of wound swabs. Colonisers were observed in 14.2% (11/77) of wound swabs. Specificity of Gram’s stain in comparison with tissue cultures was found to be 83.3% and sensitivity was 50%. Methicillin Sensitive Staphylococcus aureus (MSSA) 17.8% (05/28) and Escherichia coli 21.4% (6/28) were the major pathogens isolated from tissue cultures. Methicillin Resistant Staphylococcus aureus (MRSA) was isolated from 33.3% (13/39) of wound swabs followed by Escherichia coli (28.2%) (11/39). In the present study 25% (7/28) of tissue isolates showed Multidrug Resistance (MDR) and 3.5% (1/28) were Extended Spectrum Beta Lactamase (ESBL) producers. Among wound swabs 23% (9/39) isolates were MDR and 10.2% (4/39) were ESBL producers. Conclusion: In the present study it was observed that tissue samples were found to be better specimens in comparison with wound swabs for the diagnosis of implant infections. Hence, appropriate collection of sample helps in accurate isolation of pathogens in implant infections.