Health vigilance concerning Acinetobacter baumannii bacteremia at the mohammed VI university hospital of oujda (morocco): epidemiological profile and antibiotic resistance

The objective of this work is to determine the epidemiological profile of Acinetobacter b aumannii (A.baumannii ) bacteremia in the microbiology laboratory of CHU Mohammed VI of Oujda and its antibiotic resistance rates. This is a retrospective and descriptive study of 27 months fromJune 24, 2016to September 19, 2018 including all positive blood cultures processed in the microbiology laboratory in accordance with REMIC (reference in medical microbiology)and EUCAST(European Committee on Antimicrobial Susceptibility Testing). Contaminated blood cultures were excluded. As results we collected 863 positive blood cultures, A. baumannii accounted for 7.41% (n = 64). 67% (n =43) of the strains were isolated from patients hospitalized in intensive care (adults, children and newborns). The two main risk factors described in patients with our series were wearing of intravascular device in 55% (n=35) Immunosuppression in 22% n=14). A. baumannii bacteremia was associated with care in 37.5% (n=24). 75% (n=48) of A. baumannii isolates were resistant to carbapenems. No strain of A. baumannii was resistant to colistin. In light of these results strengthening the control and prevention measures for healthcare associated infections would be the most reliable way to limit the spread of A. baumannii in our establishment.


Introduction
A baumannii is a Gram-negative, non -motile, strictly aerobic, non-fermentative, non-sporing, coccobacillus. The ability of A. baumannii to form biofilms contributes to its survival in adverse environmental conditions including hospital environments and medical devices [1].
Of particular importance is the ability of Acinetobacter to cause bacteremia , especially in critically ill patients, the clinical course of which may range from a benign transient bacteremia to fulminant septic shock [2].
The existence of multi-resistant strains places A. baumannii among the organisms that threaten the current therapeutic management and therefore the choice of molecules during probabilistic treatment is a real challenge. Carbapenems have long been considered as the treatment of choice for Acinetobacter infections. Today, this class is threatened by the emergence of resistance, favored by its increasing use in connection with the emergence of multi-resistant enterobacteria. [3].
Patients with multi-drug resistant A. baumannii nosocomial bacteremia have longer lengths of stay, higher costs, and higher mortality rates [4].
The objective of this work is to determine the epidemiological profile of A. baumannii bacteremia and its antibiotic resistance rates.

Materials and methods
This was a retrospective and descriptive study from June 24, 2016 to September 19, 2018 and included all positive blood cultures processed in the microbiology laboratory ; Contaminated blood cultures were excluded. The results were interpreted in accordance with the recommendations of the medical microbiology reference system (REMIC) [6] .

Results: Epidemiology
During the study period, we collected 863 positive blood cultures, with A. baumannii accounting for 7.41% (n=64). The majority of A. baumannii strains were isolated from newborns, which represented 47% of cases (n=30) .19 patients were female (30%) versus 45 male (70%), representing a sex ratio of 2.36. 67% (n=43) of the strains were isolated from patients hospitalized in the intensive care unit (adults, children and neonates), by medical departments with 22% (n=14) of the isolates, and surgical departments with 5% (n=3) of the isolates, the hospital department was not specified for 6% (n=4) of the patients.
The two main risk factors described in the patients of our series were: Intravascular device wear in 55%(n=35), Immunosuppression in 22% n=14).
Bacteremia caused by A. baumannii were associated with care in 37.5% (n=24).

Resistance profile
Of the 64 strains of A. baumannii isolated in the microbiology laboratory, 87% were resistant to Ciprofloxacin and Gentamicin, 86% to Cefepime and Levofloxacin, 85% to Ceftazidime, Ticarcillin, and Ticarcillin/clavulanic acid combination, 75% (n=48) of A. baumannii isolates were resistant to carbapenems .No A. baumannii strain was resistant to colistin. ( Fig 1)  Being an opportunistic pathogen, Acinetobacter baumannii often affects fragile patients such as the immunocompromised, low birth weight neonates, and intensive care patients [11,12 ].
In our study, the average age was 25 years, which is due to the fact that about 47% of A. baumannii bacteremias were isolated in newborns. This average age is far from the data of the literature, which note a predominance in adult subjects with an average age of 67 years [2,13,14].
In the present study, we also noted a male predominance with a sex ratio of 2.36, which is in line with the data in the literature. This male predominance is reported by several studies [2 ,13,14].
The male predominance may be explained by the finding that A. baumannii bacteremia is often associated with underlying conditions such as smoking, alcoholism, diabetes and other chronic lung diseases [15]. In our study, a large proportion (67%) of A. baumannii bacteremias originated in the intensive care unit . These results are consistent with the literature, as the intensive care unit is the most common site for A. baumannii infections, but with varying rates. The rate found in this study is lower than that reported in Italy in 2019 (85%) [16] , but remains higher than that reported in Greece in 2016 (53.9%)[17].
We pointing out that only 22%(n=14) of patients were immunocompromised while 55% (n=35) of patients wore an intravascular device and. These rates are lower than those reported in Lebanon in 2017 [2] and in China in 2016 [18 ].

Resistance profile
According to a recent WHO report, A. baumannii becomes a major threat to public health when it acquires resistance to broad-spectrum antibiotics, such as carbapenems [19]. Current findings suggest that the battle against this pathogen is being lost [20] due to the limited alternatives for treating the infections it causes [21] and the lack of public health interventions to control antibiotic resistance.
From 2011 to 2014, 2337 A. baumannii were collected from 453 hospital sites in 48 countries as part of the SMART continuous surveillance initiative. Rates of multidrug-resistant acinetobacter baumannii were lowest in North America (47%) and highest in Europe and the Middle East (>93%), [22]. In our study we noted multiresistance of A. baumannii to the tested antibiotics.
The resistance to ciprofloxacin in the different studies is higher than 50% which is in line with the data of our study [23][24][25][26][27][28].
Resistance to aminoglycosides was 87% for gentamycin and 81% for tobramycin, these rates are higher than those reported in Casablanca [28] and Tunisia [27].
Our strains are less resistant to imipenem (75% in our study compared to 93% in China, 96.9% in Iran and 88.6% in Tunisia).
For the combination of trimethoprim and sulfamethoxazole 38% of our strains were resistant, this rate remains far from that reported in Casablanca (77%), Tunisia (51.5%) and China (93.4%) Colistin is the last resort for the treatment of multiresistant Acinetobacter baumannii. Unfortunately, resistance to colistin has been reported worldwide. The highest rate of resistance has been reported in Asia, followed by Europe [29]. in our study no A. baumannii strain was resistant to colistin.

Conclusion
Our study showed the important place that occupies the bacteremia with A. baumannii within our hospital structure in particular in intensive care unit, in fragile patients carriers of invasive materials or presenting a ground of immunodepression, indeed this bacteria became a not negligible therapeutic headache considering the emergence of the multi resistant strains to the antibiotics.
In light of these results, strengthening healthcareassociated infection control and prevention measures would be the most reliable way to limit the spread of A. baumannii in our institution.