Background and Aim
Recently, the extensive use of quinolones led to increased resistance to these antimicrobial agents, with different rates according to the organism and the geographical region. The aim of this study was to detect the resistance rate of
Klebsiella pneumoniae
Iraqi isolates toward quinolone antimicrobial agents, to determine genetic mutations in
gyrA
and
parC
, to screen for efflux-pump activity, and to screen the presence of plasmid-mediated quinolone resistance (PMQR) genes.
Methods
Forty-three
K. pneumoniae
isolates were confirmed phenotypically and genotypically by Vitek 2 system and species specific primers by PCR using the targeting
rpo
gene followed by sequencing. Antibiotic susceptibility test was carried out using disc diffusion method. Quinolone resistant isolates were subjected to ciprofloxacin MIC testing, and cartwheel method to screen for efflux pump activity. The presence of the plasmid mediated quinolone resistance genes
qepA, qnrB, qnrS
, and
aac(6)Ib
was tested by PCR. Sequencing of
gyr
A and
par
C was performed.
Results
We observed a high rate of resistance to ceftriaxone, gentamicin ciprofloxacin, and levofloxacin. Low rate of resistance was detected against amikacin and azithromycin. Ciprofloxacin MIC results revealed that 96.1% of the isolates had MICs >256 µg/mL, 83.4% had MICs >512 µg/mL while 34.6% had MIC >1024 µg/mL. Testing of isolates against ciprofloxacin mixed with EtBr at various concentrations resulted in decreased resistant. Sequencing results showed that Ser83Leu was the most common mutation in
gyr
A that was observed in all quinolone resistant isolates, followed by Asp87Asn. Ser80Ile mutation in
par
C was observed in 77.7% of the tested isolates. The prevalence of PMQR genes was 92.5%
aac (6)-Ib
, 51.8%
qnr
B, 40.7%
qep
A, and 37%
qnr
S.
Conclusion
Quinolone resistance is common in
K. pneumoniae
isolates in Baghdad. The frequent mutation in
gyr
A and
par
C, and the presence of PMQR genes is alarming.
Pseudomonas aeruginosa is a major cause of nosocomial infection in children and adults, resulting in significant morbidity and mortality due to its ability to acquire drug resistance. The ability of P. aeruginosa in the environment to cause infection in individuals has been reported previously; henceforth, surveillance of the emergence and transmission of P. aeruginosa strains among patients is important for infection control in a clinical setup. Various gene-typing methods have been used for epidemiological typing of P. aeruginosa isolates for the purpose of surveillance. In this work, the suitability and comparability of two typing methods, enterobacterial repetitive intergenic consensus (ERIC)-PCR and random amplification of polymorphic DNA (RAPD)-PCR fingerprinting, were studied to characterize P. aeruginosa strains isolated from clinical and environmental sources. Forty-four clinical and environmental bacterial isolates of P. aeruginosa were collected between October 2015 and January 2016. DNA extraction, ERIC-PCR and RAPD-PCR, agarose gel electrophoresis, and phylogenetic analyses were carried using the unweighted pair-group method with mean. RAPD typing revealed less clonality among clinical isolates, whereas the ERIC method showed greater similarity in comparison with RAPD. Environmental isolates, however, showed greater similarity using RAPD compared with ERIC typing. With only a few exceptions, most clinical isolates were distinct from environmental isolates, irrespective of the typing method. In conclusion, both the RAPD and ERIC typing methods proved to be good tools in understanding clonal diversity. The results also suggest that there is no relationship between clinical and environmental isolates. The absence of clonality among the clinical isolates may indicate that most P. aeruginosa infection cases could be endemic and not epidemic and that endemic infections may be due to nonclonal strains of P. aeruginosa.
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