Co-colonization of anatomical niches by microorganisms is well documented. Growth of more than one type of Gram negative bacilli (GNB) from single cultures is commonly observed in Microbiology laboratories. The study aimed to determine whether any of the patient’s demographic and/or clinical factors influence polymicrobial growth from clinical samples.Various clinical samples that grew two types of GNB from a single sample were selected for the study. In the cohort of 82 patients, the most common samples were pus (52.4%). 62.2% of the samples grew a combination of glucose Non Fermenting Gram Negative Bacilli (NFGNB) and an Enterobacteriaceae species. 40.2% samples grew a combination of a susceptible and a resistant GNB. In 69.3% of the samples there was an association between the Gram stain report (presence of inflammatory cells with or without bacteria) and clinical condition suggestive of infection, but this was not statistically significant (p = 0.322). Duration of hospital stay of more than 5 days was significantly associated with the antibiotic resistance pattern of the isolates, both by univariate (p=0.002) and multivariate (p=0.003) analysis. Similar results were seen with the pattern of porganisms isolated and their antibiotic resistance pattern.
