Risk Factors Associated with MDR and CR Acinetobacter baumannii Carriage among ICU Patients Hospitalized at MOI Teaching and Referral Hospital, Kenya

Background: Multi-drug resistant and Carbapenem-Resistant Acinetobacter baumannii (CRAB) infections present a significant challenge in hospital ICU settings worldwide and the threat posed is worse in developing countries including Kenya. Despite the limited treatment options, there is inadequate comprehensive data on factors associated with MDR and CR Acinetobacter baumannii carriage among ICU patients hospitalized at hospitals. This study therefore aimed to address this gap and determined risk factors associated with MDR and CR Acinetobacter baumannii carriage among ICU patients hospitalized at MOI Teaching and Referral Hospital, Kenya. Methods: Through cross-sectional study design, a total of 132 ICU admitted patients were purposively enrolled in this study between July 2019 and July 2020. Demographic and risk factors associated with MDR and CR Acinobacter baumannii were collected using structured questionnaire. Descriptive statistics and bivalent analysis were used for data analysis obtained. Level of statistical significance was 95% confidence interval (CI) for all analysis. Results: Bivariable analysis showed that employed participants were 3.4 times more likely to have A. baumannii compared to the unemployed (cOR = 3.38, 95%, CI: 1.09 - 10.43, p = 0.035). Patients who were having high BMI were likely to be infected by A. baumannii compared to those who had normal/low BMI (aOR = 11.2, 95%, CI: 3.57 - 21.11, p = 0.004). Those who were aged ≥ 50 years were 21 times more likely to be carbapenem-resistant Acinetobacter baumannii, COR = 21.0, 95% CI: 1.83 - 240.52, p = 0.011. Those who stayed in ICU for more than 30 days were 16 times more likely to be carbapenem-resistant Acinetobacter baumannii compared to those who had been admitted (COR = 16.0, 95% CI: 1.45 - 176.45, p = 0.019). Conclusion: Increased length of hospital stay, obesity and marital status were the factors found to be significantly associated with A. baumannii infections among ICU admitted patients. On the other hand, gender, age, level of education, occupation, referral status and presence of infection were found to have no significant association with A. baumannii infections among ICU admitted patients. All patients admitted to the intensive care units should be screened for colonization with A. baumannii, owing to the poor treatment outcomes associated with carriage of this multidrug resistant pathogen. Proper infection control in the ICU settings should be upheld to mitigate the spread of A. baumannii in the intensive care units.

Analysis on drug-resistance and molecular epidemiology of Acinetobacter baumannii isolated from the clinical samples in two Chinese hospitals

In the present study, the drug-resistance genes encoding β-lactamases, aminoglycoside modifying enzymes, DNA topoisomerases and integron as well as their molecular epidemiology were investigated by means of analyzing the drug-resistance and molecular epidemiology of Acinebacter baumannii isolated from the clinical samples in two hospitals in Changzhou and Huzhou city of Jiangsu and Zhejiang province from July 2000 to March 2005. The minimal inhibitory concentrations （MICs） of these 307 isolates were detected by automatic microbiological system, and 35 strains against 5-fluoroquinolones were performed by agar dilution assay. Meanwhile, the resistant genes in 80 isolates were amplified by PCR with identification by DNA sequencer. It was found that most of the 307 isolates of A. baumannii were resistant to multiple antibiotics tested, in which the resistance rates of the isolates against piperacillin, piperacillin/tazobactam, amoxacillin/clavulanic acid, cefotaxime, ceftazidime, cefepime, gentamicin, amikacin, ciprofloxacin, chloramphenicol and sulfamethoxazole/trimethoprim were all above 35%, but those of imipenem and meropenem were quite low, ranged only 2.6% and 3.3 %. In addition, it was also demonstrated that the positive rates of TEM and SHV β-lactamase genes accounted for 93.8% and 22.5% respectively, and those of the aminoglycoside-modifying enzyme genes including aacC1, aacC2, aacC3, aacC4, aacC4A, aphA6, ant（2″）-Ⅰ and ant（3″）- Ⅰ were 58.8%, 8.8%, 7.5%, 28.8%, 45.0%, 2.5%, 28.8% and 65.0% respectively. The mutations in the quinolone-resistant determining region （QRDR） of gyrA and parC genes indicated that substitution in Ser-83 residue of GyrA protein was most frequently occurred among strains with MIC for ciprofloxacin of more than 4 μg/ml, whereas a double mutation at Ser-83 residue of gyrA and Ser-80 of parC was found in strains with MIC of ciprofloxacin of more than 8 μg/ml. As to the positive rates of class 1 integron （Int Ⅰ -1） and qacE△1-sul-1, it was found to be 60.0% and 77.5% respectively, and the rates of resistant genes of strains isolated in these two hospitals varied considerably. The results obtained in the present study indicate the presence of the multiple resistant genes in strains of A. baumannii, and great measures should be taken to control the spread of the resistant strains carrying the resistant genes.

Correlation of the antiseptic resistance in Acinetobacter baumannii and the antiseptic resistance gene qacEΔ1 located in classⅠintegron

In the past decade, uses of antiseptics and disinfectants in hospitals and other health care centers are rather common, but the chance to develop resistance to antiseptics and disinfectants is also increased. Acinetobacter baumannii is one of the opportunistic bacteria involving in the nosocomial infection. In the present study, the correlation of the antiseptic resistance in A. baumannii and the antiseptic resistance gene qacEΔ 1 was investigated by means of determination of MICs. Meanwhile, the MICs of glutaraldehyde, chlorhexidine, benzalkonium bromide, iodophor and trichloroisocyanurate to 80 clinical isolates of A. baumannii were detected by tube dilution assay and the resistance genes intll and qacE Δ 1 in these isolates were amplified by PCR and verified by DNA sequencer. It was found that the MIC50 for these 5 antiseptics tested were 32, 8, 8, 4 and 1 μg/ml respectively, and the detection rates of intll and qacEΔ1 gene were 60.0% and 77.6% respectively. In addition, 55% of the 80 isolates simultaneously possessed both intll and qacEΔ1 gene, and the percentage of antiseptic resistance of A. baumannii carring both genes to benzalkonium bromide were higher than that without these two genes, however, there was no significant difference between intll and qacEΔ1 gene. The result in bactericidal efficiency assay indicated that chlorhexidine could still produce rapid and strong bactericidal effect at concentration of 1 MIC after 10 rain exposure. These results suggest that the antiseptic resistance of A. baumannil to various antiseptics is correlated with the presence of the antiseptic resistance genes qacEΔ 1 in bacteria, thus warning that the increase of the antiseptic resistance should not be ignored and the relative high concentration or prolonged application time is required to achieve a sufficient bactericidal effect.