Antimicrobial resistance pattern of Uro-Pathogens emphasizing non-lactose fermenting gram negative bacilli.

Objectives: To identify various species of non-lactose fermenting gram-negative bacilli involved in urinary tract infections, and to determine their antimicrobial resistance pattern. METHODS: The retrospective, descriptive, cross-sectional study was conducted from January 1 to April 1, 2022, at the Dow University of Health Sciences, Karachi, and comprised data from the institutional diagnostic laboratory that was related to urine samples regardless of age and gender from January 1, 2020, to December 31, 2021. Data was analysed using SPSS version 25. RESULTS: Of the 103,887 urine samples, 41,280(39.7%) were positive, 51,146(49.2%) showed no bacterial growth, 11,000(10.6%) had non-significant bacterial growth and 461(0.4%) had mixed bacterial growth. Of the positive samples, 18359(44.5%) were positive in 2020, and 22,921(55.5%) in 2021. Gram-negative lactose fermenting bacteria included escherichia coli 23,123(22.3%) and klebsiella pneumoniae 2,993(2.9%), gram-negative non-lactose fermenting bacteria included pseudomonas aeruginosa 1,110(1.07%), and gram-positive bacteria included enterococcus 8,008(7.7%). Pseudomonas aeruginosa was most resistant against tobramycin 880(79.3%) and least resistant against piperacillin-tazobactam 146(13%). CONCLUSIONS: Piperacillin-tazobactam was highly sensitive drug against non-lactose fermenting uro-pathogens.

Distribution of the invasive pathogenic isolates in blood culture with their antimicrobial susceptibility pattern in a diagnostic laboratory in Karachi.

OBJECTIVE: To determine the frequent bacterial pathogens causing blood stream infections in various age brackets, and to discover their antibiotic susceptibility pattern. METHODS: The retrospective, descriptive, observational, cross-sectional study was conducted at the microbiology laboratory of Patel Hospital, Karachi, and comprised positive blood culture bacterial isolates analysed between July 1, 2018, and June 30, 2019. Standard microbiological techniques were employed for the identification and antimicrobial susceptibility testing. Data was analysed using SPSS 20. RESULTS: Of the 3450 specimen, 1243(36%) were positive; 668(53.7%) from male and 575(46.3%) from female subjects, and 771(62%) were gram-positive whereas 472(38%).were gram-negative. Salmonella typhi was the most common pathogen 139(11.1) among gram-negative organisms, followed by Acinetobacter species 103(8.2%), Escherichia coli 96(7.7%) and Klebsiella species 42(3.4%). Among gram-positive bacteria, the predominant isolates were staphylococcus epidermidis 650(52%), staphylococcus aureus 67(5.4%) and enterococci 28(2.3%). Linezolid (99.8%), vancomycin (99%) and chloramphenicol (69%) were found to be the most sensitive antibiotics among gram-positive cocci. Meropenem (60%), amikacin (46%) and gentamicin (40%) were the most sensitive antibiotics for multidrug resistant gram-negative bacteria. CONCLUSIONS: The identification of frequent bacterial pathogens in blood cultures of patients may guide clinicians in proper empirical selection of antibiotics in patients with bacteraemia.

Mutational Frequencies in Mycobacterial rpoB gene using GeneXpert/MTB Rif Assay in Rifampicin Resistant patients at a tertiary care setting in Urban Sindh, Pakistan: Analysis from a Five-Year Period.

OBJECTIVES: To assess the mutational frequencies in Mycobacterial rpoB gene using GeneXpert/MTB Rif Assay in rifampicin resistant patients during 2013-2017 at a tertiary care setting in Urban Sindh, Pakistan. METHODS: This Retrospective Descriptive Cross-Sectional Study was conducted at the TB laboratories, Ojha Institute of Chest Diseases, Dow University of Health Sciences. The record of 713 positive cases of Rifampicin Resistant Tuberculosis from January 2013 to December 2017 were analysed. These were diagnosed using GeneXpert® that detects mutations in the 81 base pair region of rpoB gene with the help of five molecular probes A, B, C, D and E. All invalid and extra pulmonary samples were excluded. RESULTS: In total, 713 cases were found to be rifampicin resistant during the five-year period, among which 374 (52.45%) were males while 339 (47.55%) were females. Among the five standard probes A, B, C, D and E, 97.48% of the cases had a single mutation. Among these, mutations in Probe E (66.48%) were the most common, followed by Probe B (14.3%) and Probe D (11.08%). Only 13 cases (1.82%) of double mutations and five cases (0.7%) of triple mutations were detected. CONCLUSION: The rpoB gene Probe E region 529-533 appears the most potent site for a mutation and development of rifampicin resistance in the rpoB gene in Mycobacterium tuberculosis, that encodes the ß-subunit of RNA polymerase. The most affected age-group in both males and females is 19-45 Years.

HBV S antigen evolution in the backdrop of HDV infection affects epitope processing and presentation.

INTRODUCTION: HBV can evolve under selection pressure exerted by drugs and/or host immunity, resulting in accumulation of escape mutations that can affect the drug or the immune activity. Hepatitis delta virus (HDV) coinfection is also known to exert selection pressure on HBV, which leads to selective amplification of certain mutations, especially in genes that are required for HDV pathogenesis, such as HBsAg. However, little is known about the function of these mutations on HBV or HDV life cycle. The purpose of this study is to determine mutations selectively amplified in the backdrop of HDV, and how these mutations affect processing of CD4- and CD8-T cell epitopes. METHODS: HBsAg was successfully amplified from 49/50 HBV mono- and 36/50 coinfected samples. The sequences were used to identify mutations specific to each study group, followed by an in silico analysis to determine the effect of these mutations on (1) proteasomal degradation, (2) MHC-I and MHC-II biding, and (3) processing of T-cell epitopes. RESULTS: HBV-HDV coinfected sequences exhibited certain unique mutations in HBsAg genes. Some of these mutations affected the generation of proteasomal sites, binding of HBsAg epitopes to MHC-I and -II ligands, and subsequent generation of T- cell epitopes. CONCLUSION: These observations suggest that HBV selectively amplifies certain mutations in the backdrop of HDV coinfection. Selective amplification of these mutations at certain strategic locations might not only enable HBV to counteract the inhibitory effects of HDV on HBV replication but also facilitate its survival by escaping the immune response.