Susceptibility of methicillin-resistant Staphylococcus aureus and enterococci to teicoplanin in Pakistan: the MRSET study.

OBJECTIVE: To evaluate the susceptibility pattern of S. aureus and enterococci to teicoplanin using an in vitro method. METHODS: Between February and November 2011, valid bacteriological samples were collected at three hospitals in three cities in Pakistan and the organism was isolated. Only samples containing S. aureus or enterococci were tested for their sensitivity to teicoplanin and various other standard antimicrobials in therapy, using the disc diffusion testing by the Kirby-Bauer method. SPSS 18 was used for statistical analysis. RESULTS: Of the 401 isolates collected, a majority 293 (59.6%) were methicillin-sensitive S. aureus, while 136 (33.9%) were methicillin-resistant S. aureus; and 26 (6.5%) were enterococci. All isolates were sensitive to teicoplanin and vancomycin. CONCLUSION: Teicoplanin had the same in vitro sensitivity as vancomycin against methicillin-sensitive S. aureus, methicillin-resistant S. aureus and enterococci in clinical isolates.

Prevalence of multi drug resistant Acinetobacter baumannii in the clinical samples from Tertiary Care Hospital in Islamabad, Pakistan.

BACKGROUND & OBJECTIVES: Acinetobacter baumannii can cause a wide range of infections, including bacteremia, pneumonia, urinary tract infection, peritonitis, etc. This organism is becoming resistant to a large group of antibiotics, especially ß-lactam antibiotics. The reason for multi-drug resistance may be the production of extended- spectrum ß-lactamses (ESBLs), carbapenemases/metallo ß-lactamases or AmpC ß-lactamases. The aim of the present study was to determine the prevalence of multi-drug resistant Acinetobacter baumannii isolated from the patients in Surgical Intensive Care Units (SICUs) of Pakistan Institute of Medical Sciences (PIMS), Islamabad, Pakistan. METHODS: A total of 91 A. baumanni isolates were collected from PIMS during the period from February 2011 to December 2011. The antibiotic susceptibility testing was performed by standard disc diffusion method as recommended by CLSI. Combination disc method, Modified Hodge test, EDTA disc synergy test and AmpC disc test were performed for detection of ESBLs, carbapenemases, metallo ß-lactamases, and AmpC ß-lactamases, respectively. RESULTS: The prevalence of MDRs was reported 100% among A. baumannii. The antibiotic susceptibility profile showed that minocycline and tigecycline were the most effective drugs against A. baumannii. Almost all of A. baumannii isolates were carbapenemase and metallo ß-lactamase producers. AmpC prevalence was observed in 41.76%, while none of the isolates was ESBL producer. Antibiogram and minimal inhibitory concentrations (MICs) indicated tetracycline is relatively effective against A. baumanii. CONCLUSIONS: Increased frequency of multi-drug resistance supports the need for continuous surveillance to determine prevalence and evolution of these enzymes in Pakistan.

Prevalence of plasmid-mediated AmpC ß-lactamases in Escherichia coli and Klebsiella pneumonia at tertiary care hospital of Islamabad, Pakistan.

Enterobacteriaceae produces AmpC ß-lactamases that make them resistant to commonly used antibiotics. AmpC ß-lactamases can be chromosomal-mediated or plasmid-mediated AmpC ß-lactamases (PABLs). The present study was undertaken to determine the occurrence of PABLs production in clinical isolates in Escherichia coli and Klebsiella pneumoniae. Among 1328 culture positive samples, 511 isolates were identified as E. coli (81.02%, n = 414) and K. pneumonia (18.98%, n = 97). Cefoxitin resistance was observed in E. coli (19.57%, n = 81) and K. pneumoniae (22.68%, n = 22). Out of these cefoxitin resistant isolates, 40.74% (n = 33) E. coli and 54.55% (n = 12) K. pneumoniae came out to be PABL producers. Prevalence of both PABLs and ESBLs in E. coli and K. pneumoniae was 29.24% (n = 8) and 47% (n = 5), respectively. Isolates coproducing PABLs and ESBL exhibited increased minimum inhibitory concentrations (MICs) for selected cephalosporins. This study documented a high frequency of PABLs producing isolates from hospital which may lead to serious therapeutic problem.