gyrA ser83 mutation among fluoroquinolone-resistant Salmonella enterica serovars from enteric fever patients in tertiary care hospital, Kathmandu.

BACKGROUND: The management of enteric fever through antibiotics is difficult these days due to the emerging resistance of Salmonella to various antimicrobial agents. The development of antimicrobial resistance is associated with multiple factors including mutations in the specific genes. To know the current status of mutation-mediated fluoroquinolone-resistance among Salmonella enterica serovars; Typhi, Paratyphi A, B and C, this study was focused on detecting gyrA ser83 mutation by restriction digestion analysis of gyrA gene using HinfI endonuclease. RESULTS: A total of 948 blood samples were processed for isolation of Salmonella spp. and 3.4% of them were found to be positive for Salmonella growth. Out of the 32 Salmonella isolates, 2.2% were S. Typhi and 1.2% were S. Paratyphi A. More interestingly, we observed less than 5% of isolates were resistant to first-line drugs including chloramphenicol, cotrimoxazole and ampicillin. More than 80% of isolates were resistant to fluoroquinolones accounting for 84.4% to levofloxacin followed by 87.5% to ofloxacin and 100% to ciprofloxacin by disc diffusion methods. However, the minimum inhibitory concentration method using agar dilution showed only 50% of isolates were resistant to ciprofloxacin. A total of 3.1% of isolates were multidrug-resistant. Similarly, 90.6% of the Salmonella isolates showed gyrA ser83 mutation with resistance to nalidixic acid. CONCLUSIONS: The increased resistance to fluoroquinolones and nalidixic acid in Salmonella isolates in our study suggests the use of alternative drugs as empirical treatment. Rather, the treatment should focus on prescribing first-line antibiotics since we observed less than 5% of Salmonella isolates were resistant to these drugs.

Higher Rate of Extreme Drug-resistant Klebsiella pneumoniae Infections among Cardiac Patients.

BACKGROUND: The accelerating rate of carbapenems resistance in Klebseilla pneumoniae isolates has put the treatment option worrisome. The effective strategy to ameliorate this alarming situation is possible through enhancing the combination therapy and appropriate laboratory diagnosis. Hence, the study was focused on identifying carbapenemase-producing K. pneumoniae and their antibiogram pattern. METHODS: A total of 944 clinical samples from patients attending Sahid Gangalal National Heart Center were processed from September 2019 to March 2020 to identify the possible bacterial pathogens following the standard microbiological procedures. K. pneumonaie isolates were further subjected to antibiotic susceptibility testing by the modified Kirby Bauer disc diffusion technique. Phenotypic confirmation of carbapenemase production was done by the modified carbapenemase inactivation method. The minimum inhibitory concentration of colistin was determined by the broth microdilution method. RESULTS: Of the total 944 samples, 15.47% (146) samples showed bacterial growth, among which 23.97% (35) were K. pneumoniae. Out of 35 K. pneumoniae isolates, 45.71% (16) were multidrug-resistant followed by 42.86% (15) extensively drug-resistant. Fourteen isolates of K. pneumoniae were carbapenemase producers among which 20% (7) were serine carbapenemase while 20% (7) showed metallo-?-lactamase production. All the carbapenemase-producing K. pneumoniae were susceptible to colistin with <0.125µg/ml. Carbapenemase activity showed statistically significant with multidrug resistance (p=<0.05). CONCLUSIONS: An increasing resistance to the carbapenem drugs showed a great problem in the management of K. pneumoniae infections among immunocompromised patients especially cardiac patients however, colistin can be still an ultimate choice of drug for disease management.