Bacterial incidence and antibiotic sensitivity pattern in moderate and severe infections in hospitalised patients.

Infectious diseases are among the leading causes of death and sometimes curable. Bacteria are the most common aetiology in hospitalised patients. Objectives of this study were to evaluate the incidence of bacterial infections and their pattern of susceptibility to antibiotics in moderate and severe infections in hospitalised patients. The study was performed in the apical teaching hospital of West Bengal in the first half of 2005. Patients admitted in medical wards and medical ICU, suffering from moderate and severe infections having APACHE-II score > 5 were studied. Clinical evaluation, routine and specific investigations were done in each case. Microbiological samplings were tried on day 1, after completion of antibiotic therapy and in between as required. Aerobic BACTEC bacterial culture and sensitivity tests were done. Pending initial culture and sensitivity report empiric antibiotic therapy was started, which was modified on getting the culture and sensitivity report. Outcome was observed as no response, cured, resolved, inconclusive, died and left against medical advice. Out of 40 patients total number of samples were 54 and that of sites of infections were 48. Primary site could not be detected in 11 infections (22.9%). Commonest form was urinary tract infection and abdominal infection in community acquired infection (n=18) and pneumonia in hospital acquired infection (n = 15). Culture was positive in 33 (61.11%), Gram-negative infection was more common in general, but incidence of Gram-positive infection was also quite high and Gram-positive infection was more common in community acquired infection. In general S aureus was most common bacteria -8 (24.24%). In community acquired infection S aureus 4 (22.22%) predominated followed by E coli and in hospital acquired infection S aureus -4 (26.66%) followed by E coli and P aeruginosa. Incidence of methicillin resistant Staph aureus was low. But it constituted 50% of S aureus. No methicillin resistant Staph aureus was found in community acquired infection. Two isolates of vancomycin intermediate sensitive Staph aureus were observed. Methicillin resistant Staph aureus showed maximum sensitivity to linezolid (100%) and all methicillin resistant Staph aureus but one vancomycin intermediate sensitive Staph aureus were sensitive to vancomycin. Coagulase negative Staph aureus were all sensitive to vancomycin and linezolid. Gram-negatives were mostly resistant to aminoglycosides and P aeruginosa were all sensitive to aztreonam. Single strain of S typhi as isolated was resistant to ceftriaxone and ciprofloxacin. P miribalis, P aeruginosa and coagulase negative Staph aureus were notoriously multidrug resistant; 82.5% of cases responded to treatment of which 35% were cured microbiologically. Gram-negative infection was more common overall, but incidence of Gram-positive infection was also very high. Gram-negative infections were responsible for more severe infections and case fatality. Multidrug resistant Gram-positive infections are rising.