Evaluation of the current trend of nalidixic acid susceptibility in typhoidal Salmonellae; a marker of therapeutic failure for the fluoroquinolones

BACKGROUND AND OBJECTIVES

Typhoid is a major health problem faced by the developing countries like Pakistan. More than 20 million cases are reported annually worldwide. Currently fluoroquinolones are the drugs of choice to treat typhoid fever. In vivo resistance to fluoroquinolones leading to therapeutic failure is developing rapidly and is becoming a major concern for the clinicians. The objective of this study was to determine the sensitivity pattern of Nalidixic acid over the last four years

MATERIAL AND METHODS

A descriptive cross sectional study was carried out at the Microbiology Department of the Army Medical College, National University of Sciences and Technology, Rawalpindi from January 2006 to December 2009. All the isolates were dealt with standard microbiological procedures. The antimicrobial sensitivity of Nalidixic acid and Ciprofloxacin was determined using Kirby-Bauer disc diffusion method as per the guidelines of Clinical and Laboratory Standard Institute (CLSI).

RESULTS

Out of 240 isolates, 111 were Salmonella typhi and 129 were Salmonella paratyphi A. The resistance of the typhoidal Salmonella to Nalidixic acid has reached significant levels and it seems only a matter of time when hundred percent resistance will be encountered. All isolates were sensitive to Ciprofloxacin on disc diffusion method.

CONCLUSION

Resistance to Nalidixic acid predicting therapeutic failure with fluoroquinolones is on a steady rise.

Sensitivity pattern of methicillin resistant Staphylococcus aureus isolated from patients admitted in a tertiary care hospital of Pakistan

BACKGROUND AND OBJECTIVES

Methicillin resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen causing significant morbidity and mortality. The aim of this study was to evaluate in vitro activities of different antibiotics against methicillin resistant Staphylococcus aureus.

MATERIALS AND METHOD

The study was conducted over a period of one year (January 2009 - December 2009) in the Department of Microbiology, Army Medical College, the National University of Sciences and Technology, Pakistan. One hundred and thirty-nine Methicillin resistant Staphylococcus aureus isolated from the clinical specimens at Rawalpindi Military Hospital were subjected to in vitro susceptibility against various antimicrobials using Kirby Bauer disc diffusion technique.

RESULTS

All the isolated MRSA organisms were uniformly susceptible to vancomycin, linezolid and tigecycline. Other drugs which were found to be effective were chloramphenicol, and rifampacin. Most of the MRSA were isolated from pus samples.

CONCLUSION

Vancomycin, tigecycline and linezolid were effective against methicillin resistant strains of S.aureus. This study suggests that chloramphenicol and rifampacin also have good in vitro efficacy for methicillin resistant S. aureus infections. Oral dosing option for linezolid, chloramphenicol and rifampacin can allow earlier discharge of hospitalized patients and thus reduce health care expenses as well as help reduce the chances of vancomycin resistant strains emergence.