Pattern of antimicrobial resistance of Gram-negative bacilli in surgical site infections in in-patients and out-patients at an apex trauma Center: 2013–2016

INTRODUCTION: Antimicrobial resistance is an increasing problem worldwide especially among the surgical site infections (SSIs). SSI is becoming more serious due to hospital-acquired infections/nosocomial infections, which further leads to the overuse of broad-spectrum antibiotics. To investigate the antimicrobial resistance patterns among Gram-negative bacteria in SSI in in- and out-patients the present study was designed. METHODOLOGY: During the 4 years (January 2013–December 2016), the antimicrobial resistant pattern was studied in the admitted patients and in the patients who were followed up to the outpatients department (OPD) after discharge. Antimicrobial resistance pattern testing was done by the disk diffusion method on Mueller-Hinton agar and by E-test for ten antibiotics according to The Clinical and Laboratory Standards Institute guidelines for Gram-negative bacilli. RESULTS: A total of 2,447 strains were isolated from the studied population on over the period of 4 years. Of 2447, 1996 (81%) were isolated from patients who had SSI during the hospital stay, and 451 (18%) were from patients who attended the OPD after discharge. In the outpatients, who followed up in the OPD for the SSI, Escherichia coli (148), and Pseudomonas aeruginosa (93), whereas in the patients who develop SSI during their hospital stay, Acinetobacter baumannii (622), E. coli (424), and Klebsiella pneumoniae (315) were found to be common. A very high resistance pattern was observed in both the studied groups; however, a higher resistance pattern was seen in in-patients as compared to outpatients. CONCLUSION: In our study, we have reported resistance pattern in Gram-negative bacteria isolated from the patients who were came for the follow as well as in the inpatients. For the outpatients, it can be concluded that it could be a community-acquired infection which is also an alarming condition for our society

Molecular mechanisms of colistin- and multidrug-resistance in bacteria among patients with hospital-acquired infections

Aim: The increasing burden of resistance in Gram-negative bacteria (GNB) is becoming a major issue for hospital-acquired infections. Therefore, understanding the molecular mechanisms is important. Methodology: Resistance genes of phenotypically colistin-resistant GNB (n = 60) were determined using whole genome sequencing. Antimicrobial susceptibility patterns were detected by Vitek®2 & broth microdilution. Results: Of these phenotypically colistin-resistant isolates, 78% were also genetically resistant to colistin. Activation of efflux pumps, and point-mutations in pmrB, and MgrB genes conferred colistin resistance among GNB. Eight different strains of K. pneumoniae were identified and ST43 was the most prominent strain with capsular type-specific (cps) gene KL30. Discussion: These results, in combination with rapid diagnostic methods, will help us better advice appropriate antimicrobial regimens

Epidemiological investigation and successful management of a Burkholderia cepacia outbreak in a neurotrauma intensive care unit

Objective: The detailed epidemiological and molecular characterization of an outbreak of Burkholderia cepacia at a neurotrauma intensive care unit of a level 1 trauma centre is described. The stringent infection control interventions taken to successfully curb this outbreak are emphasized. Methods: The clinical and microbiological data for those patients who had more than one blood culture that grew B. cepacia were reviewed. Bacterial identification and antimicrobial susceptibility testing was done using automated Vitek 2 systems. Prospective surveillance, environmental sampling, and multilocus sequence typing (MLST) were performed for extensive source tracking. Intensive infection control measures were taken to further control the hospital spread. Results: Out of a total 48 patients with B. cepacia bacteraemia, 15 (31%) had central line-associated blood stream infections. Two hundred and thirty-one environmental samples were collected and screened, and only two water samples grew B. cepacia with similar phenotypic characteristics. The clinical strains characterized by MLST typing were clonal. However, isolates from the water represented a novel strain type (ST-1289). Intensive terminal cleaning, disinfection of the water supply, and the augmentation of infection control activities were done to curb the outbreak. A subsequent reduction in bacteraemia cases was observed. Conclusion: Early diagnosis and appropriate therapy, along with the rigorous implementation of essential hospital infection control practices is required for successful containment of this pathogen and to curb such an outbreak. Keywords: Burkholderia cepacia, Outbreak, Neurotrauma unit, MLST typing, Novel ST typ