Prevalence of MDR and ESBL producing Gram-negative isolates from 1 various clinical samples from patients visiting a tertiary care hospital in 2 Kathmandu,

ESBL producers was performed as recommended by the CLSI and the confirmatory test was performed phenotypically using the E-test. Out of 92 isolates, 84 (91.3%) isolates were multidrug resistant, and 47 (51.1%) isolates were 29 found to be potential ESBL producers. Of these, 16 isolates were confirmed ESBL producers 30 by the E-test. Escherichia coli and Klebsiella pneumoniae were the predominant isolates and 31 were also the major ESBL producers. Besides polymyxin B (100% sensitive), meropenem 32 and imipenem showed high efficacy against the ESBL producers. Multidrug resistance was very high, however, ESBL production was low. Polymyxin B and carbapenems are the choice of drugs against ESBL producers but should be used only as the last line drugs.

4 strip was carried out by testing the strips with standard ATCC strains (E. coli ATCC 25922 and Data analysis 100 SPSS v16.0 was used for statistical analysis. Chi-square test was applied at 95% CI among 101 demographic variables. 102

103
A total of 92 Gram-negative bacteria were isolated from various clinical specimens. K. 104 pneumoniae (n=35) and E. coli (n=29) were the predominant isolates. Highest number of the 105 organism was isolated from urine (n=52) followed by sputum (n=18) ( Table 1). A total of 39 and 106 50 organisms were isolated from the inpatient department and outpatient department, respectively. 107 The highest number of organisms were isolated from the age-group above 60 and the least from 108 the age-group 11-20 (Table 3). There was no significant difference in growth positivity between 109 males and females (p=0.134); however, growth positivity in urine was significantly higher in 110 females (77.3%) than in males (37.5%) (p=0.012). 111 effectiveness to ESBL producers. Meropenem and imipenem were sensitive to around 75% of the 120

Demographic distribution of MDR isolates and ESBL producers 144
The prevalence of MDR was higher in males, whereas ESBL production was dominant in 145 females. MDR prevalence was very high in all age groups. ESBL production was higher in the 146 age-groups 31-40 years and 41-50 years. The percentage of MDR isolates was higher in outpatient 147 compared to the inpatient, whereas ESBL production was higher in isolates from inpatient than 148 the outpatient. Among the samples, MDR was seen very high, i.e., 80% or above, in isolates from 149 all the samples except pus. ESBL producers were dominant in urine and absent in pus, wound, 150 and tissue samples (Table 3). 151

DISCUSSION 152
In this study, 11.9% of the samples showed growth positivity. However, higher rates of growth 153 positivity have been reported in similar studies in Nepal [20,21,22,23]. In this study, the highest 154 number of growth was observed in the urine sample which was in agreement with that reported by a higher prevalence of E. coli and K. pneumoniae was observed. Similar outcomes were drawn by 161 Saderi et al. [26] and Yadav and Prakash [27]. Another study by Shrestha et al. [28] also unveiled 162 E. coli as the most common organism. 163  Polymyxin B and carbapenems seem to be the choice of drugs against ESBL producers and Gram-214 negative bacteria. However, these drugs should be considered as alternatives until we have other common Gram-negative bacteria seemed to change over time, a recent antibiogram for different 217 Gram-negative isolates might help physicians in treating bacterial infections [44]. 218

CONCLUSIONS 219
The present study revealed a very high MDR prevalence (91.3%) though ESBL production 220 (19.0%) was low. Therefore, regular surveillance of MDR and ESBL producers and 221 implementation of hospital infection control policies to prevent the transmission of such isolates 222 is much required. Polymyxin B and carbapenems seem to be the choice of drugs against ESBL 223 producers and Gram-negatives but should be considered as alternatives until we have other 224 sensitive drugs that could be administered safely. 225

Limitations 226
There were a few limitations to our study. Firstly, the sample size was around 770, which seemed 227 to be significantly less than in other studies. The study was conducted within a short duration, i.e., 228 six months. The data taken was purely obtained from only one hospital, which might not represent 229 the whole population. Only a phenotypic study was performed. Studies on the molecular level