Benchmarking institutional geriatric hip fracture management: a prelude to a care quality improvement initiative.

BACKGROUND: Fractures around the hip in older adults have increased in the last two decades, and the numbers are projected to rise over the next 30 years with estimates that half of them will occur in Asia. Proximal hip fractures should be operated within 48 h of injury to prevent poor outcomes. This study aims to benchmark current hip fracture care using quality improvement tools of care structure, care processes, and outcomes in a tertiary care hospital in Eastern India and determine the evidence-practice gaps and barriers to implementing the six best practices that reduce mortality and morbidity in fragility hip fractures. METHODS: A total of 101 consecutive patients above 50 years of age with proximal femoral fractures after a trivial fall were included. Patients were divided into two groups: those operated within [Group A] and beyond [Group B] 72 h of admission. Care structure assessment included delays in admission, delay in surgery, and anesthesia risk grading. Care processes included the type of surgery performed and postoperative complications. The primary outcomes were the 30-day and 1-year mortality and the secondary outcomes included the length of stay, mobility at 6 months, return to pre-fracture independence, activity limitations, pressure sores, and readmission to the hospital. RESULTS: Group A comprised 26 individuals, and the remaining 75 were in Group B. There were two deaths in Group A as compared to one death in Group B at 30 days; however, there were no new deaths at 1 year in Group A and 14 deaths in Group B (p = 0.187). Group B had lengthier hospital stays, poorer mobility, and higher physical and mental difficulties. No patients had re-operation on the initial fracture. CONCLUSION: This study emphasizes the importance of early admission and fast provision of surgical fixation to reduce mortality and morbidity. Benchmarking institutional practices allows for defining the evidence-practice gaps and barriers to best practice implementation. This is an essential step to begin care quality improvement for geriatric patients with proximal femur fragility fractures.

P-type ATPase zinc transporter Rv3270 of Mycobacterium tuberculosis enhances multi-drug efflux activity.

Metal homeostasis is maintained by the uptake, storage and efflux of metal ions that are necessary for the survival of the bacterium. Homeostasis is mostly regulated by a group of transporters categorized as ABC transporters and P-type ATPases. On the other hand, efflux pumps often play a role in drug-metal cross-resistance. Here, with the help of antibiotic sensitivity, antibiotic/dye accumulation and semi-quantitative biofilm formation assessments we report the ability of Rv3270, a P-type ATPase known for its role in combating Mn2+ and Zn2+ metal ion toxicity in Mycobacterium tuberculosis, in influencing the extrusion of multiple structurally unrelated drugs and enhancing the biofilm formation of Escherichia coli and Mycobacterium smegmatis. Overexpression of Rv3270 increased the tolerance of host cells to norfloxacin, ofloxacin, sparfloxacin, ampicillin, oxacillin, amikacin and isoniazid. A significantly lower accumulation of norfloxacin, ethidium bromide, bocillin FL and levofloxacin in cells harbouring Rv3270 as compared to host cells indicated its role in enhancing efflux activity. Although over-expression of Rv3270 did not alter the susceptibility levels of levofloxacin, rifampicin and apramycin, the presence of a sub-inhibitory concentration of Zn2+ resulted in low-level tolerance towards these drugs. Of note, the expression of Rv3270 enhanced the biofilm-forming ability of the host cells strengthening its role in antimicrobial resistance. Therefore, the study indicated that the over-expression of Rv3270 enhances the drug efflux activity of the micro-organism where zinc might facilitate drug-metal cross-resistance for some antibiotics.

The MSMEG_1586 of M. smegmatis Is a Penicillin-Interactive Enzyme That Can Potentially Hydrolyse Aztreonam and Cephalosporins.

Mycobacteria are intrinsically resistant to beta-lactams as they possess several putative penicillin-interactive enzymes (PIEs), some of those are with dual-activity, namely DD-carboxypeptidase and beta-lactamase. Here, with help of molecular approaches, we elucidated the nature of one such putative PIE, MSMEG_1586, in Mycobacterium smegmatis. The in vivo expression of the membrane-bound form of MSMEG_1586 enhanced the beta-lactam resistance of a beta-lactamase deleted host E. coli strain (AM1OC), particularly for aztreonam (eight-fold) and cephalosporins (8-16 fold). To understand the reason for such elevation of resistance, soluble-form of MSMEG_1586 (sMSMEG_1586) was created by removing signal peptides and partially eliminating the amphipathic helix, and finally, expressed and purified. The purified sMSMEG_1586 was active and manifested a strong penicillin-binding affinity as shown by its ability to bind to fluorescent penicillin (Bocillin-FL). Interestingly, the steady-state kinetics apparently confirmed the hydrolytic ability of sMSMEG_1586 towards cefotaxime and aztreonam where hydrolysing aztreonam is a unique and rare behaviour among the beta-lactamases. However, sMSMEG_1586 was devoid of exerting DD-carboxypeptidase like activity. Finally, in silico analysis of MSMEG_1586 revealed a special folding that resembles class C beta-lactamase, except for the absence of a characteristic R2 loop. Overall, MSMEG_1586 could be categorized as a cephalosporinase with the ability to hydrolyse aztreonam.

Involvement of the non-active site Residues in the Catalytic Activity of NDM-4 Metallo beta-lactamase.

The rise of New Delhi metallo beta-lactamase (NDM) producing bacteria imposes a significant threat to the treatment of bacterial infections due to their broad spectrum against beta-lactams. The activity of metallo beta-lactamases is affected by active site residues as well as residues near the active site. Therefore, we aimed to identify the amino acid residues around the active site of NDM-4 which influence its function. To achieve that, seven substitution mutations (S191A, D192A, S213A, K216A, S217A, D223A and D225A) of NDM-4 were generated through site-directed mutagenesis. Out of these, expression of NDM-4_D192A and NDM-4_S217A in Escherichia coli cells increased the beta-lactam susceptibility as compared to NDM-4. Further, proteins were purified to assess the effect of substitution mutations on zinc content, in vitro catalytic efficiency, and stability of NDM-4. The catalytic efficiency was reduced for these mutants (D192A and S217A) towards beta-lactam substrates, while the thermal stability remained insubstantial as compared to NDM-4. However, the purified NDM-4_D192A exhibited altered zinc content. In silico studies reveal that these changes might be the outcomes of alterations in hydrogen bonding networks and substrate interactions. Taken together, we infer that the D192 and the S217 residues play a substantial role in the activity of NDM-4.