Sensitivity Pattern of Second Line Anti-Tuberculosis Drugs against Clinical Isolates of Multidrug Resistant Mycobacterium Tuberculosis

Objective: To determine the current sensitivity pattern of second line anti-tuberculosis drugs against clinical isolates of Multidrug Resistant Mycobacterium tuberculosis [MDR-TB]. Study Design: A cross-sectional study. Place and Duration of Study: Department of Microbiology, Armed Forces Institute of Pathology [AFIP], Rawalpindi, from November 2011 to April 2013. Methodology: Samples received during the study period were processed on BACTEC MGIT 960 system for Mycobacterium tuberculosis [MTB] culture followed by first line drugs susceptibility testing of culture proven MTB isolates. On the basis of resistance to rifampicin and isoniazid, 100 clinical isolates of MDR-TB were further subjected to susceptibility testing against amikacin [AMK], capreomycin [CAP], ofloxacin [OFL] and ethionamide [ETH] as per st and ard BACTEC MGIT 960 instructions. Results: Out of 100 MDR-TB isolates, 62% were from male patients and 38% from female patients. 97% were sensitive to AMK, 53% to OFL, 87% to CAP; and 87% were sensitive to ETH. Conclusion: The majority of the MDR-TB isolates showed excellent sensitivity against AMK, CAP and ETH. However, sensitivity of MDR-TB isolates against fluoroquinolones like OFL was not encouraging. Key Words: Multidrug resistant tuberculosis. Mycobacteria growth indicator tube. Second line anti-tuberculosis drugs. Amikacin. Capreomycin. Ethionamide

Extensively and pre-extensively drug resistant tuberculosis in clinical isolates of multi-drug resistant tuberculosis using classical second line drugs [levofloxacin and amikacin]

To find out the frequency of Extensively Drug Resistant [XDR] and pre-XDR tuberculosis in clinical isolates of Multi-Drug Resistant [MDR] Tuberculosis [TB] by determining the susceptibilities against Levofloxacin and Amikacin [classical second line antituberculosis drugs]. A descriptive cross-sectional study. Microbiology Department, Armed Forces Institute of Pathology [AFIP], Rawalpindi, from September 2011 to August 2013. Amikacin [AK] and Levofloxacin [LEVO] were obtained in chemically pure form from Sigma [Taufkirchen, Germany]. The breakpoint concentration used for AK was 1.0 microg/ml and for LEVO 2.0 microg/ml. Mycobacterial Growth Indicator Tube [MGIT] 960 system was used to carry out drug susceptibility testing as per recommended protocol. A total of 3 MDR-TB isolates [3%] turned out to be XDR-TB based upon simultaneous resistance to injectable second line antituberculosis drug AK and one of the fluoro-quinolones [LEVO]. A total of 24 MDR-TB isolates [24%] were found to be pre-XDR based upon resistance to LEVO alone. Treatment status record of patients with XDR and pre-XDRTB isolates revealed that majority of patients had received fluoroquinolones [FQs] during the course of treatment. XDR-TB has started to emerge in MDR-TB isolates in our set up. The worrying sign is the high frequency of pre-XDR tuberculosis. Urgent steps need to be taken to stem the tide of pre-XDR-TB in our population. It is thus recommended to develop facilities to carry out drug susceptibility testing to monitor the status of pre-XDR and XDR-TB in our population

Antimicrobial susceptibility pattern of bacteria isolated from patients with urinary tract infection

To determine the antimicrobial susceptibility pattern of bacterial pathogens in the patients of urinary tract infection reporting at a tertiary care hospital. Laboratory based study. Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi, from January to December 2012. A total of 440 culture positive bacterial isolates from 1110 urine samples; submitted over a period of one year were included in this study. Identification of bacterial isolates was done by standard biochemical profile of the organisms. The antimicrobial susceptibility of culture positive bacterial isolates was performed by disk diffusion method as recommended by Clinical Laboratory Standard Institute guidelines [CLSI]. Out of the 440 culture positive urine samples, 152 [34.6%] were from indoor patients whereas 288 [65.4%] from outdoor patients. Gram negative bacteria accounted for 414 [94%] of the total isolates while rest of the 26 [6%] were Gram positive bacteria. The most prevalent bacterial isolate was Escherichia [E.] coli 270 [61.3%] followed by Pseudomonas [P.] aeruginosa 52 [12%] and Klebsiella [K.] pneumoniae 42 [9.5%]. The susceptibility pattern of E. coli showed that 96.2% of the bacterial isolates were sensitive to imipenem, 85.1% to amikacin, 80.7% to piperacillin/tazobactam and 72.6% to nitrofurantoin. In case of P. aeruginsosa, 73% bacterial isolates were sensitive to tazobactam/piperacillin, 69.2% to sulbactam/cefoperazone and 65.38% to imipenem. The antibiogram of K. pneumoniae has revealed that 76.1% of the bacterial isolates were sensitive to imipenem and 52.3% to piperacillin/tazobactam. Nitrofurantoin and imipenem were the most effective antimicrobials amongst the Enterococcus spp. as 92.3% showed susceptibility to this bacterial isolate. Majority of the bacterial isolates were sensitive to imipenem and piperacillin/tazobactam while susceptibility to most of the commonly used oral antibiotics was very low. Among the oral antimicrobials, nitrofurantoin showed good susceptibility against Enterobacteriaceae family and Gram positive organisms

In vitro activity of fosfomycin tromethamine against extended spectrum beta-lactamase producing urinary tract bacteria

To determine the in vitro activity of Fosfomycin tromethamine against extended spectrum beta-lactamase producing uropathogens. Experimental study. Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi, from October 2011 to October 2012. A total of 381 culture positive ESBL producing isolates from 2400 urine samples submitted over a period of one year were included in this study. Identification of isolates was done by standard biochemical profile of the organisms. The antimicrobial susceptibility of culture positive isolates was performed by disk diffusion method as recommended by Clinical Laboratory Standard Institute guidelines [CLSI]. The antimicrobial activity of Fosfomycin to various isolates revealed that 93% of E. coli, 64% Klebsiella spp. 50% Proteus spp. 75% Enterobacter cloacae, 100% Citrobacter freundii, 100% Burkholderia spp. 100% Serratia spp. and 50% Stenotrophomonas maltophilia were susceptible to this chemical compound. Fosfomycin showed excellent effectiveness to most of the common ESBL producing bacteria such as E. coli, Klebsiella and Proteus spp

Pathogens causing blood stream infections and their drug susceptibility profile in immunocompromised patients

To determine the types of pathogens causing blood stream infections and their drug susceptibility profile in immunocompromised patients. Cross-sectional, observational study. Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi, from January to September 2012. Blood culture bottles received from immunocompromised patients were dealt by two methods, brain heart infusion [BHI] broth based manual method and automated BACTEC system. The samples yielding positive growth from either of two methods were further analyzed. The identification of isolates was done with the help of biochemical reactions and rapid tests. Antimicrobial susceptibility of the isolates was carried out as per recommendations of Clinical and Laboratory Standards Institute [CLSI]. Out of the 938 blood culture specimens received from immunocompromised patients, 188 [20%] yielded positive growth. Out of these, 89 [47.3%] isolates were Gram positive and Gram negative each, while 10 [5.3%] isolates were fungi [Candida spp.]. In case of Gram positive isolates, 75 [84.3%] were Staphylococcus spp. and 51 [67%] were Methicillin resistant. Amongst Gram negative group 49 [55.1%] isolates were of enterobacteriaceae family, while 40 [44.9%] were non-lactose fermenters [NLF]. In vitro antimicrobial susceptibility of Staphylococci revealed 100% susceptibility to vancomycin and linezolid. The enterobacteriaceae isolates had better susceptibility against amikacin 85.7% compared to tigecycline 61.2% and imipenem 59.2%. For NLF, the in vitro efficacy of aminoglycosides was 72.5%.The frequency of Gram positive and Gram negative organisms causing blood stream infections in immunocompromised patients was equal. Vancomycin in case of Gram positive and amikacin for Gram negative organisms revealed better in vitro efficacy as compared to other antibiotics.