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Introduction: Antibiotic resistance in the last decade has recorded drastic changes in an increasing manner in nonfermenting bacterial groups of gram-negative bacilli including Ps. aeruginosa is a potent bacterial isolate or opportunistic nosocomial human pathogen. In recent decades, with improvements in antimicrobial therapy and diagnostic procedures have emerged multidrug resistant with beta lactamase to β-lactam antibiotics in presence of carbapenemases group of enzymes as metallo β-lactamases (MBL) are a major cause of concern. Due to its transferable character, it can hydrolyze almost all antibiotics. So, the study has conducted the detection of MBL isolates in hospital. Materials and Methods: In the study, 134 nonrepetitive clinical isolates of Pseudomonas spp. from the In Patient Department (IPD) patients attended to hospital from different clinical and isolates were confirmed in the department of microbiology and tested by the Kirby-Bauer disc diffusion method, which were screened for MBL production by disc synergy test as double-disc synergy test (DDST), combined-disc synergy test, and Modified Hodge test (MHT). The test was observed by a zone of inhibition of antibiotic with EDTA discs was ≥7 mm antibiotic disc alone as positive. MHT by the presence of a 'cloverleaf shaped' zone of inhibition was considered positive. Data were statistically analyzed and generated the graphs, whereas categorical variables (age and gender) were described in a descriptive way. Prevalence and percentage were used to establish an association of risk factors with carbapenem resistance strains. Result: A total of 134 Ps. aeruginosa was obtained from various clinical samples as 56 were found maximum in pus. Thirty nine bacterial isolates were found carbapenem resistant and in which 24 males (61.5%) were higher than 15 females (38.5%) in the 41-50 years age group. Carbapenem-resistant strains screened were for MBL production and found maximum by MHT test showed positive with meropenem (76.92%) and imipenem (71.79%). Isolates were found maximum in inpatients from surgical ward 45 (33.58%). Also, carbapenem-resistant isolates were found maximum from surgery (18). Four patients developed surgical site infections, had ulcerative lesions viz. traumatic, nondiabetic ulcer and from intensive care unit, 2 patients clinically identified as ventilated associated pneumonia (with COPD), 1 was immunocompromised with respiratory failure and COPD died in study. Discussion: Carbapenem resistant Ps. aeruginosa was found especially among critically ill patients. Isolates were found predominantly among males in the 41-50 years age group of patients. All 39 isolates were found resistant to meropenem, 32 (82.05%) bacterial isolates were resistant to both meropenem and imipenem where 7 (17.95%) isolates were found resistant to meropenem but sensitive to imipenem. MHT test was used to detect carbapenems activity but it does not give the confirmation of metal dependence of the carbapenems none of the phenotypic tests were optimal due to lower sensitivity or specificity. DDST has less channel of subjective variation, but combined-disc synergy test interprets more. The test between meropenem and meropenem with EDTA disc enhanced by diffusion method demonstrates the better synergy test (also for imipenem) and detection of carbapenem-resistant are not statistically significant [calculated P value is. 12 (P value >.05)]. The Minimum Inhibitory concentration (MIC) antibiotic susceptibility testing by E-test for imipenem and meropenem defines the use for the future. The surgical department found the highest prevalence may be due to the patient being treated by another hospital and was on third-line medication of cephalosporins. This may be due to higher comorbidity, invasive procedures, nonhealing ulcers after surgery, longer stay in the hospital, and excessive use of broad-spectrum antibiotics. The study was observed in economically weaker patients; seasonal trends of patient's admission and due to rural area tertiary healthcare centers awaiting improvement of the facility which may associate admission avoidance by the patient. Conclusion: MBL production was identified as the resistant mechanism of resistance carbapenems group of drugs including another group of antibiotics; prevalence was found similar to other studies but the resistance to another group of antibiotics was found lower. Also, disc diffusion method was reliable for screening with a correlation of DDST or MHT. Our study was focused to improve hospital infection control by the prevalence of organisms and their related risk factors, which may help in care and treatment of patients after admission. Evaluation still needs to conclude a positive association as per our study. E-test–based testing and molecular detection were not done in all isolates.

Chryseobacterium indologenes is gram-negative bacteria that cause infection in humans. It is less frequently isolated in the laboratory. The development of drug-resistant and its intrinsic ability to resist a wide range of antimicrobials enables them to cause mortality in an immunocompromised patient with a longer hospital stay. Our study objectives are to investigate antimicrobial-resistant patterns, drug-resistant enzymes, and the risk factor analysis associated with multidrug-resistant (MDR), extensively drug-resistant (XDR), and Pan-drug resistant (PDR) within 2 years. Altogether 53 strains of Chryseobacterium indologens were obtained from 5000 specimens that were processed for routine bacterial culture. The bacterial identification was done using conventional techniques (colony morphology, gram staining, flexirubin test, and biochemical tests) as well as the VITEK-2 System to further confirm. The bacterial isolate were processed to observe antimicrobial susceptibility test (AST) using disk diffusion method. MDR XDR and PDR were classified following European Centre for Disease Prevention and Control guidelines. C. indologens strains with beta-lactamases such as extended-spectrum beta-lactamases (ESBL), metallo beta-lactamases (MBL), and Amp-C beta-lactamases (Amp-C) were detected phenotypically. The highest isolation of C. indologens was observed in a sputum sample. In vitro antimicrobial susceptibility test revealed susceptibility to tigecycline followed by levofloxacin, cotrimoxazole, and piperacillin-tazobactam. From 53 isolates of C. indologens, MDR accounts for 56.60% and 22.64% for XDR. Combined antimicrobial therapy and longer hospital stay were found to be the leading risk factor. All 53 C. indologenes strains were detected as MBL. Total ESBL was detected in 16.98% of MBL producer strains and Amp-C was observed in 13.20% of MBL-producing strains. All 3 enzyme co-oproducers were seen in only 5.66% of C. indologens. Although it is rarely encountered in the laboratory, it showed a remarkable effect in patients with underlying predisposing factors and prolonged hospital stays. The presence of betalactamases determined the drug-resistant activity on a wide spectrum of tested antibiotics. [ABSTRACT FROM AUTHOR]

New Delhi Metallo beta-lactamase (NDM) is of significant public health concern due to its enormous potential to hydrolyse all major beta-lactams including carbapenems. Amino acid substitutions outside the active site reportedly affect NDM beta-lactamase activities. Here, the effect of amino acid substitutions in the possible omega-like loop region of NDM-5 has been elucidated. Overall, three substitution mutations near active site of NDM-5 were done, namely, E152A, S191A and D223A and subsequently, the change in antimicrobial resistance was monitored upon expressing each mutant in a suitable host. Among the three mutants, E152A substitution on a loop near the active site resulted in significant reduction in beta-lactam antibiotic resistance as compared to NDM-5 that compelled us to conduct further studies on the E152A-substituted NDM-5. The purified NDM-5 was able to hydrolyse all the beta-lactams tested whereas the E152A mutation suppressed its activities. NDM-5 showed maximum kcat/Km ratio against penicillins and carbapenems and had lower Km as compared to NDM-5 E152A. Though, the amino acid substitution did not affect the overall folding pattern of NDM-5, significant differences in thermal stability between the wild-type and mutated protein were observed. Therefore, we infer that the E152 residue is important in regulating the beta-lactam hydrolysing properties of NDM-5. [ABSTRACT FROM AUTHOR]