Genetic characterization of methicillin-resistant / susceptible Staphylococcus aureus (MRSA/MSSA) and Staphylococcus argenteus clinical isolates in Bangladesh: Dominance of ST6-MRSA-IV/t304 and detection of cfr/fexA in ST8-MSSA/t008

Objectives

Coagulase-positive staphylococcus (CoPS), represented by Staphylococcus aureus, is a major cause of infections in humans. This study aimed to investigate molecular epidemiological characteristics, antimicrobial resistance, and their trends of CoPS in Bangladesh.

Methods

Clinical isolates of CoPS were collected from two medical institutions in Bangladesh for a 2-year period and analyzed for their species, genotypes, virulence factors, antimicrobial susceptibility, and resistance determinants.

Results

172 CoPS isolates collected were identified as S. aureus or S. argenteus (170 and two, respectively). Methicillin-resistant S. aureus (MRSA) accounted for 36% (n = 61), having Staphylococcal cassette chromosome mec (SCCmec)-IV (82%) or V (18%). Panton-Valentine leukocidin (PVL) genes were detected at higher rate in methicillin-susceptible S. aureus (MSSA) (62%) than MRSA (26%). MRSA comprised 11 STs, including a dominant type ST6 (46%) associated with mostly SCCmec-IVa/spa-t304, and one isolate had genetic features of the USA300 clone (ST8/SCCmec-IVa/coa-IIIa/spa-t008/ACME-I/ΦSa2USA). STs of CC1, CC88, and CC398 were common in MSSA, with CC88 showing the highest PVL-positive rate. One MSSA isolate (ST8/spa-t008) harbored fexA and cfr showing susceptibility to linezolid. S. argenteus was methicillin-susceptible and belonged to ST2250/coa-XId.

Conclusions

Genetic characteristics of current MRSA/MSSA in Bangladesh were revealed, with first identification of S. argenteus at low prevalence.

Efficacy of Probiotics in Treatment of Acute Rotavirus and Non Rotavirus Watery Diarrhoea in Children Admitted in Mymensingh Medical College Hospital

Probiotics are live microorganisms that, when administered in adequate amount helps in reducing the duration of diarrhoea. Objective of this double blind randomized controlled clinical trial was to assess the efficacy of probiotics in treatment of acute rotavirus & non rotavirus watery diarrhoea among children aged 6 months to 2 years admitted at diarrhoea corner of Paediatrics Department of Mymensingh Medical College Hospital from October 2017 to May 2019. It was a double blind randomized controlled clinical trial. Total 500 sample were divided into Group A=ORS, zinc plus placebo (n=250) and Group B=ORS, zinc plus probiotics (n=250). Both Group A and Group B consisted of children presented with rotavirus and non-rotavirus diarrhoea. Placebo or probiotics were given once daily for 5 days which was prepared and coded by department of Pharmacology. Stool specimens were taken to Microbiology Department of MMCH for rotavirus detection. Rotavirus was detected by Polyacrylamide gel electrophoresis (PAGE). Data was analyzed by computer using SPSS program version 23.0. A total of 500 children with acute watery diarrhoea were included. Among them 188 children were diagnosed as rotavirus positive. Among group A found 89 rotaviral and 161 non rotaviral diarrhoea patients. Among group B found 99 rotaviral and 151 non rotaviral diarrhoea patients. Baseline characteristics were similar in both groups. The duration of diarrhoea, hospital stay, and fever was significantly lesser in probiotics group when compared with control (p<0.001). But duration of vomiting did not reduce significantly in probiotics group. Frequency of stools reduced significantly in probiotics group.

Seropositivity of Human Brucellosis among Patients with Pyrexia of Unknown Origin on Both Risk and Non-Risk Group of Individuals and Molecular Detection by Real-time PCR

Brucellosis is a zoonotic disease that is one of the important infectious causes of Pyrexia of Unknown Origin (PUO). The objective of the present study was to determine the seropositivity and molecular detection of human brucellosis among the patients with pyrexia of unknown origin on both risk and non-risk group of individuals in greater Mymensingh. A total of 400 blood samples were randomly collected from pyretic patients started from September 2018 to August 2019. Questionnaires were used to collect data on both risk and non-risk group of individuals. All samples were initially screened for anti-Brucella antibodies using the Brucella-specific latex agglutination test. For accurate investigation, seropositive as well as seronegative serum samples were tested by BCSP31 Brucella genus-specific TaqMan real-time PCR. Overall 32(8%) cases were positive out of 400 samples by Brucella-specific latex agglutination test and/or BCSP31 Brucella genus-specific real-time PCR. Brucella-specific latex agglutination test documented 7% (28/400) positivity for brucellosis. 22(5.5%) samples found Brucella genus-specific real-time PCR positive out of 400 samples. Most real-time PCR positive cases were found from sero-positive samples of risk group population (15/32). Sero-negative but real-time PCR positive cases also found only from risk group population (4/32). There were 10 seropositive cases where real-time PCR was negative. In addition to Brucella-specific latex agglutination test as a screening test, Brucella genus-specific real-time PCR was performed for confirmation and also to avoid unjustified costs, drug toxicity, and masking of other potentially dangerous diseases.

Molecular Detection of Human Brucellosis among Patients with Pyrexia of Unknown Origin

This study describes the molecular detection of human brucellosis among patients with pyrexia of unknown origin. It was a cross-sectional descriptive study and was carried out in the Department of Microbiology, Mymensingh Medical College, Mymensingh, Bangladesh. Non-probability purposive type of sampling technique was used. Blood samples were collected from 400 pyretic patients from September 2018 to August 2019. BCSP31 Brucella genus-specific TaqMan real-time PCR and SYBR Green real-time PCR were undertaken for molecular detection. Out of 400 samples, 22 (5.5%) samples found BCSP31 Brucella genus-specific real-time PCR positive. The study revealed that a considerable number of brucellosis is present in rural areas among risk as well as non-risk group study population having definite male predominancy, most prone to develop among >40-80 years age group. Brucella genus and species-specific real-time PCR might be performed for confirmation and also to avoid unjustified costs, drug toxicity, and un-masking of other potentially dangerous diseases.

SARS-CoV-2 Detection using Real Time PCR by a Commercial Diagnostic Kit

There is a new public health problem around the world with the emergence and spread of 2019 novel corona virus (2019-nCoV). The disease "coronavirus disease 2019" (COVID-19) was caused by SARS-CoV-2. As virus isolates are unavailable so the public laboratories are now facing a challenge for detecting the virus because there is growing evidence of the outbreak which is more widespread than initially thought. We aimed here to discuss about the current diagnostic methodology for detecting the SARS-CoV-2 in health laboratories. Here we use the Novel Corona virus (2019-nCoV) Nucleic Acid Diagnostic Kit (PCR-Fluorescence Probing) which is a real time reverse transcription polymerase chain reaction (rRT-PCR) test. A total of 230 samples in the department of microbiology, Mymensingh Medical College from 1st, April 2020 were selected for this study. Among them 20(8.69%) were positive for SARS CoV-2 and remaining were negative. Among the positive samples 55% could amplify both the ORF 1ab and N genes. The single gene ORF 1ab or N was positive in 15% and 30% cases respectively. The Ct values (<38) of ORF 1ab gene indicated by FAM dye was 92.8% and N gene curve indicated by ROX dye was 100%. The presence of IC gene curve with Ct values (<38) indicated by CY5 dye among the positives were 70% and 100% in negatives. The Ct values (38-40) of IC (CY5) among the positives were 15%. The present study demonstrates the enormous response capacity of the study kit for detecting SARS-CoV-2 within the laboratories in Bangladesh.

Co-circulation of dengue virus type 3-genotype I and type 2-Cosmopolitan genotype in 2018 outbreak in Dhaka, Bangladesh

Dengue virus (DENV) that caused an outbreak in Dhaka, Bangladesh during 2018 was analysed phylogenetically. DENV samples were classified into type 2-Cosmopolitan genotype (54%) and type 3-genotype I (46%), indicating co-circulation of two DENV types and resurgence of type 3 associated with genotype replacement.

The use of neuroendocrine immunoperoxidase markers to predict chemotherapy response in patients with non-small-cell lung cancer

Small-cell lung cancer (SCLC), a chemotherapy-responsive disease, is characterized by neuroendocrine properties. In contrast, non-small-cell lung cancer (NSCLC) is at best moderately responsive to chemotherapy, and only 10% to 20% of cases demonstrate neuroendocrine properties. The present study is a retrospective analysis of the use of immunoperoxidase markers for neuron-specific enolase (NSE), Leu-7, and chromogranin A in NSCLC patients treated with chemotherapy. It was designed to determine if the presence of neuroendocrine markers predict for response to chemotherapy. The diagnostic slides and blocks were obtained on 52 NSCLC patients who were treated with chemotherapy (26 responders and 26 nonresponders). Immunoperoxidase studies were performed, and slides were scored without knowledge of the patient's response. Markers were positive in responders and nonresponders, respectively, as follows: NSE, 14 of 26 (54%) versus seven of 26 (27%), P = .04; Leu-7, 11 of 25 (44%) versus five of 26 (19%), P = .08; and chromogranin A, three of 26 (12%) versus 0 of 26 (0%), P = .71. Two markers were positive in 10 of 26 responders (38%) and 0 of 26 nonresponders (0%), P less than .01. Responders with two or more positive markers showed superior survival (median, 79 weeks) compared with responders with fewer than two positive markers (median, 51 weeks) and nonresponders (median, 27 weeks). These data suggest that the presence of neuroendocrine markers in NSCLC is associated with an increased likelihood of response to chemotherapy and may add to the standard parameters (performance status, weight loss) used to select patients for chemotherapy.