ABSTRACT
A new subspecies of Staphylococcus hominis described by Kloos et al. in 1998 and named S. hominis subsp. novobiosepticus (SHN) has been implicated in nosocomial outbreaks. Multidrug resistance, including resistance to novobiocin and oxacillin, is a particularly important feature of SHN. In our institute, we encountered 13 cases of S. hominis subsp. hominis in cancer patients with septicemia, of which seven were methicillin resistant. The isolates were identifi ed by VITEK® 2 compact automated system, using GP REF 21342 identifi cation card and antimicrobial susceptibility testing card P-628. The biochemical reactions and antibiotic susceptibility pattern of the seven methicillin-resistant isolates were re-analyzed and patient details were re-checked to fi nally identify them as SHN. The increasing number of cases reporting isolation of SHN from biological specimens point to potential virulence and clinical importance of this bacterium.
ABSTRACT
Context: Bacterial isolates from intra-abdominal infections, in particular, peritonitis and their unpredictable antimicrobial resistance patterns, continue to be a matter of concern not only globally but regionally too. Aim: An attempt in the present study was made to study the patterns of drug resistance in bacterial isolates, especially gram negative bacilli in intra-abdominal infections (IAI) in our hospital. Materials and Methods: From 100 cases of peritonitis, identifi cation of isolates was done as per recommended methods. Antimicrobial susceptibility and extended-spectrum betalactamase (ESBL) testing were performed following the CLSI guidelines. Results: A total of 133 clinical isolates were obtained, of which 108 were aerobes and 22 anaerobes. Fungal isolates were recovered in only three cases. Escherichia coli (47/108) emerged as the most predominant pathogen followed by Klebsiella spp. (27/108), while Bacteroides fragilis emerged as the predominant anaerobe (12/22). Among coliforms, 61.7% E. coli and 74.1% Klebsiella spp. were ESBL positive. A high level of resistance was observed for beta lactams, ciprofl oxacin, amikacin, and ertapenem. Ertapenem resistance (30-41%) seen in coliforms, appears as an important issue. Imipenem, tigecycline, and colistin were the most consistently active agents tested against ESBL producers. Conclusion: Drug resistance continues to be a major concern in isolates from intra-abdominal infections. Treatment with appropriate antibiotics preceded by antimicrobial resistance testing aided by early diagnosis, adequate surgical management, and knowledge of antibiotic - resistant organisms appears effective in reducing morbidity and mortality in IAI cases.