Acid fast cysts in diarrheal stool samples of HIV positive patients

Background: Gastrointestinal infections are very common in patients with HIV infection or AIDS, and diarrhea is a common clinical presentation of these infections. Acid fast protozoans are very commonly responsible for diarrhea in HIV positive patients leading to death in many cases.Methods: The study group included 50 HIV seropositive patients suffering from diarrhea and the control group included 50 HIV seronegative patients suffering from diarrhea. The stool samples collected were concentrated using formol-ether concentration technique and stained using modified Ziehl-Neelsen’s staining procedure.Results: Among the diarrheal stool samples of HIV positive patients (n=50), 17 (34%) were positive for acid fast cysts, and among the HIV negative stool samples (n=50), 2 (4%) were positive for acid fast cysts. Cryptosporidium oocysts were detected in 15 (30%) and Isospora oocysts in 2 (4%) of the samples in the study group. Cryptosporidium oocysts were detected in 2 (4%) of the samples in the control group. There existed a significant difference between the positivity of HIV-positive and HIV-negative diarrheal stool samples.Conclusion: Timely and effective diagnosis could help in delivering appropriate treatment in an already immunocompromised patient.

Neonatal sepsis due to Weeksella virosa

Weeksella virosa was previously included in group II f of CDC. We here present the Microbiological characteristics of the isolate from a case of neonatal sepsis at our center. The organism is a non-fermenter growing only on blood agar and not on Mac Conkey agar, oxidase and catalase positive, and negative for several other bio-chemical tests, except for indole with Ehrlich’s reagent. The isolate in the present case study was sensitive to aminoglycosides and β- lactams, and resistant to quinolones and carbapenems

Urinary isolates with special reference to Urichrom II

Urinary tract infections (UTIs) are the second most common infections, only after respiratory tract infections. Conventionally, Blood agar (BA), Mac Conkey agar (MAC) and Cysteine Lactose Electrolyte Deficient (CLED) medium are used routinely for processing of urine samples. Several chromogenic media are now available which can be used to allow more specific and direct differentiation of bacterial colonies on the primary plate itself. The following study was conducted to evaluate the advantages of URICHROM II over the conventional media in supporting the growth for routine urinary isolates. The study was conducted over a one year period (January 2012 to December 2012) at Hyderabad. A total of 3094 urine samples were processed during the one year period. The urine samples were inoculated on to blood agar (BA), Mac Conkey agar (MAC) and URICHROM II. The inoculated plates were incubated at 37°C over night (16-20 hr) and examined the next day morning. Samples showing significant bacterial growth (>105CFU/ml) were further processed. A total of 3094 urine samples were processed over a one year period. Out of the 3094 urine samples processed, 945 samples were positive (30.54%) and 2149 samples (69.45%) were negative. Among the positive samples (945), Gram positive isolates were obtained from 201 samples (21.22%) and Gram negative isolates from 744 samples (78.82%). Escherichia coli was the predominant Gram negative isolate (51.11%) and Enterococcus feacalis was the predominant Gram positive isolate (14.81%). URICHROM II supported the growth of all routine urinary isolates on par with BA and MAC and can be recommended as a primary plating medium for recovery of uropathogens.

Objective structured practical examination as a formative assessment tool for IInd MBBS microbiology students

Background: Assessment drives learning. It is well known that conventional or Traditional Practical Examination (TPE) has several limitations, especially in terms of subjectivity. In OSPE the procedures are standardized, so objectivity is ensured and also reliability maximized. Objectives of the study were to compare TPE & OSPE examination in formative assessment for IInd MBBS microbiology students on the topic culture media and to obtain feedback from students attending OSPE, and faculty.Methods: 76 students were taught about culture media and simultaneously were sensitized about OSPE and TPE, which followed the next week. Informed consent was taken. All students were randomly divided into 2 batches (TPE and OSPE) based on roll call. 71 students were tested, 33 for OSPE and 38 for TPE. Eight OSPE stations were set up with 8 culture media, plus a rest station after station 4. TPE students went for viva-voce to one examiner for same eight culture media. Both OSPE and TPE students were evaluated for a score of 20. OSPE students and the faculty were given a pre-validated questionnaire for feedback.Results: Mean scores, standard deviation (SD) and “p” values were calculated using the T-test from the scores obtained. The mean scores for OSPE and TPE were found to be statistically significant- p-value <0.01. Feedback from OSPE students & faculty was also evaluated.Conclusions: OSPE is more structured and eliminates examiner bias better, and should be practiced in formative assessments and also be introduced in summative assessments