Antibiotic resistAnce profile of Klebsiella pneumoniae strAins isolAted in An infectious diseAses clinic

Objective. To establish the resistance profile of Klebsiella pneumoniae (KP) strains isolated in the Craiova Infectious Diseases Clinic. Material and method. Retrospective study (January 2017-December 2018); KPs were identified using the automated Vitek 2 system, which subsequently established their susceptibility to antimicrobials (usual testing for 17 antibiotics, extended testing for another 9); for each strain the multiple antibiotic resistance index (MAR) was calculated (limits: 0-1); the information was entered into an Excel database. 45 strains were tested in 2017 and 290 in 2018. The percentage of MDR strains was calculated based on internationally accepted definitions. results. 335 strains were identified, the vast majority isolated by sputum culture (192 strains 57.31%). Demographic data: 330 strains (99%) were isolated in adult subjects, 190 (57%) in male patients, 185 (55%) in patients living in urban areas. The overall value of MAR was 0.37 (compared to 0.32 for all strains of isolated Gram-negative germs). Over 80% of KP strains were susceptible to Amikacin or Polymyxin E; susceptibilities between 60 and 79% were observed for Meropenem, Gentamicin, Tobramycin, Ciprofloxacin, Ertapenem, Trimethoprim-Sulfamethoxazole, Levofloxacin, Cefepima, and between 40 and 59% for Ceftriaxone, Cefoxitin, Ceftazidime, Minocycline and Im. Less than 39% of strains are susceptible to Ampicillin (± Sulbactam), Piperacillin (± Tazobactam), Ticarcillin (± Clavulanic acid), Aztreonam, Pefloxacin, Cefazolin, Nitrofurantoin. Resistance to the main classes of antibiotics shows lower values than national and european data for 3rd generation cephalosporins, fluoroquinolones and aminoglycosides, but a much higher percentage of resistance to carbapenems. Over 68% of isolates are multidrug-resistant (MDR); over 60% of the strains come from sources where there is a significant contact with antimicrobials. conclusions. Over 80% of the isolated strains are sensitive to Amikacin or Polymyxin E; a percentage of over 29% of the strains demonstrates resistance to the carbapenem class in 2018; over 68% of isolates are multidrug-resistant; over 60% of the strains come from sources where there is significant contact with antimicrobials.

otics. The bacillus has been a "problem" germ since 1971, when a number of cases have been described with Gentamicin-resistant strains [5], after that, in the 90s, cephalosporin-resistant strains became an impediment to the treatment of patients [6], and now the spread of beta-lactamase-producing strains take on the character of a true epidemic [7][8][9]. It can be said that KP is one of the most important bacteria involved in nosocomial infections.
It is important for clinicians to know the general antibiotic resistance of KP strains in the area in which they operate, for a rapid and appropriate therapeutic response.

ObJEctIVE
Establishing the resistance profile of the Klebsiella pneumoniae (KP) strains isolated in the Infectious Diseases Clinic from Craiova (within the "Victor Babeş" Infectious Diseases and Pneumoftiziology Hospital).

MAtErIAL AND MEtHOD
Retrospective study (January 2017-December 2018) based on data from the hospital laboratory register; GNB and, in particular, KP were identified using the Vitek 2 automated system, which subsequently established their susceptibility to antimicrobials; most strains (317, 94.62%) were tested to 17 antibiotics, the exact situation being shown in Figure 1; for each strain the multiple antibiotic resistance index (MAR) was calculated (limits: 0-1). 45 strains were tested in 2017 and 290 in 2018. An Excel database was compiled for analysis. rEsULts 335 strains were identified (out of a total of 1,358 GNB strains, KP being the second most important bacteria in this group (24.66%), after Escherichia coli.

Demographic data
The median age of the patients was 64 years (with limits between <1 year -88 years); 330 strains (98.50%) were isolated in adult subjects, 190 (56.71%) in male patients, 185 (55.22%) in patients living in urban areas. The vast majority of KP were isolated from sputum (192 strains, 57.31%) or urine culture (123 strains -36.71%). An exact situation of the patho- logical products from which the bacillus was isolated is presented in Table 1. It should be noted that, in pediatric patients, KP was only isolated from urine samples.
The KP resistance profile for a particular antibiotic test is shown in Table 2.
The overall MAR value was 0.37 (compared to 0.32 for all strains of isolated Gram-negative germs). Figure 3 graphically shows the distribution of KP strains according to the values of MAR fractions. Table 3 shows the variation of the KP resistant strains percentage to different classes of antibiotics in two consecutive years (2017 and 2018).

DIscUssIONs
The resistance to aminopenicillin of KP strains in our clinic was on average 99.7% (100% in 2017 and 99.66% in 2018); resistance to this class of antimicrobials is practically no longer mentioned either by the ECDC report, or by the CARMIN-ROM study [3,4]. Most likely, we will give up this type of testing in the Craiova clinic as well.
Resistance to 3rd generation cephalosporins in the EU averaged 31.2-31.7% in the EU (2017 and 2018); in 2018 Romania was on the 4th place at European level, with an average percentage value of 61.4%, slightly below the value registered in 2017 (62.5% -ECDC [3], respectively 63.4% -CARMIN [4]). Our data show a resistance of 60% in 2017, respectively 46.21% in 2018 (significantly lower than the values presented previously).
Fluoroquinolone resistance of KP isolates in Romania is 1.5-2 times above the European average values (31.5-31.6% in 2017 and 2018 [3]), being 64.1% in 2017 (66.5% according to CARMIN-ROM [4]), slightly decreasing in 2018, to the percentage value of 57.4. In our clinic, however, the situation is much different, the resistance to Ciprofloxacin and Levofloxacin being on average 30.15% (28.89 in 2017, respectively 30.34% in 2018, when a significantly higher number of strains were tested).
Regarding the resistance to aminoglycosides, the European average level was 22.7-24.1% in two con-   [3,4]. The data obtained by us show a percentage value of 33.3% in 2017, decreasing to 26.9% in 2018 (but based on a number of tests over 6 times higher), regional values much different from those recorded at the national or european level. The lowest KP resistance was recorded for Amikacin (almost 4 times lower than for Gentamicin or Tobramycin). A similar situation was recorded for Escherichia coli strains [10].
For 2018, the percentage of KP resistance to carbapenems in the EU is 7.5%, slightly increasing compared to 2017 -7.2% [3]; Romania ranks 3rd, with a percentage almost 4 times higher than European data (29.5% in 2018), also increasing compared to 2017 -22.5%. The CARMIN-ROM study confirms the data for 2017, identifying a percentage of 22.5% carbapenem-resistant KP strains [4]. Our data show, similar to what we found for EC strains [10], a percentage of resistance to Meropenem, Ertapenem or both of 37.79 in 2017, respectively 29.31 in 2018. Due to the small number of strains tested not we considered the data for Imipenem-Cilastatin.
Polymyxin-resistant strains have been described, mostly in systemic infections or in special hosts, with a significant impact on case mortality [11][12][13][14]. The CARMIN-ROM study identified 55.8 percent Colistin-resistant KP strains among the already carbapen-em-resistant isolates; In contrast, of the carbapenemsensitive strains, only 5 of 104 strains (4.8%) also demonstrated resistance to polymyxins [4]. In our clinic, three strains were resistant to Colistin (0.89% of the total strains), out of a number of 23 isolates tested.
According to the definition criteria for multidrug resistance (MDR) and extended antimicrobial resistance (XDR) [15] we identified 68.86% of KP strains as MDR, but we did not register any XDR strains.
Based on Krumperman's criteria [16], we identified 206 KP strains (61.49%) with a MAR index of over 0.2, suggesting that most of the analyzed strains came from sources with significant exposure to antibiotics (most likely nosocomial).

cONcLUsIONs
Over 80% of the isolated strains are susceptible to Amikacin or Polymyxin E; compared to the national or european data (with reference to our country), the data from the Infectious Diseases Clinic from Craiova show lower percentages of resistance to the class of 3rd generation cephalosporins, fluoroquinolones or aminoglycosides, but much higher for carbapenems; a percentage of over 29% of the strains demonstrates resistance to the carbapenem class in 2018; over 68% of isolates are multidrug-resistant; over 60% of the strains come from sources where there is significant contact with antimicrobials.