Carriage of class 1 and 2 integrons in acinetobacter baumannii and pseudomonas aeruginosa isolated from clinical specimens a and a novel gene cassette array: blaOXA-11-cmlA7

Antibiyotik direnç genlerinin bakteriler arasındaki yayılımı, enfeksiyon hastalıklarının tedavisinde ciddi sorunlar oluşturmaktadır. Son zamanlarda bu genlerin integronlarda da taşındığı gösterilmiştir. Ülkemizde, Acinetobacter baumannii ve Pseudomonas aeruginosa klinik izolatlarında sınıf 1 ve sınıf 2 integron taşıyıcılığıyla ilgili çalışmalar sınırlı sayıdadır. Bu çalışmada, Abant İzzet Baysal Üniversitesi Hastanesinde, klinik örneklerden izole edilen A.baumannii ve P.aeruginosa suşlarında, sınıf 1 ve 2 integron taşıyıcılığının araştırılması ve antibiyotik direnç gen kasetlerinin dizi analiziyle karakterize edilmesi amaçlanmıştır. Çalışmaya, Mart 2010-Aralık 2012 tarihleri arasında çeşitli klinik örneklerden (%56 balgam, %19 yara, %11 idrar, %11 kan, %3 kateter) izole edilen 77 A.baumannii ve 60 P.aeruginosa olmak üzere toplam 137 suş dahil edilmiştir. İzolatların tanımlanması ve antibiyogramları Vitek 2 Compact (bioMérieux, Fransa) ve BD Phoenix 100 (Becton Dickinson, ABD) sistemleriyle yapılmıştır. Suşlarda integron varlığı, sınıf 1 (intI1) ve sınıf 2 (intI2) integraz bölgeleri için özgül primer çiftleri kullanılarak PCR yöntemiyle araştırılmış; integron amplifikasyonunun gerçekleştirildiği tüm örnekler, hem klonlanarak hem de PCR ürünü olarak DNA dizi analizine tabi tutulmuştur. Çalışmada, A.baumannii suşlarında en yüksek duyarlılık kolistin (%96) ve tigesiklin (%78), P.aeruginosa suşlarında ise piperasilin-tazobaktam (%97) ve piperasiline (%93) karşı saptanmış; buna karşın A.baumannii suşlarında en yüksek direnç oranı (%95) piperasilin/tazobaktama karşı gözlenmiştir. A.baumannii suşlarının %33 (26/77)’ünde, P.aeruginosa suşlarının ise %10 (6/60)’unda intI1 geni tespit edilmiş; intI1 pozitif suşlarda değişken bölgeler PCR ile çoğaltıldığında sekiz (8/77, %10) A.baumannii ve üç (3/60, %5) P.aeruginosa suşunun antibiyotik direnç gen kaseti taşıdığı belirlenmiştir. Suşların hiçbirisinde intI2 geni saptanmamıştır. İntegron pozitif olan tüm A.baumannii suşlarında piperasilin/tazobaktam, seftazidim, sefepim, seftriakson ve ampisilin/sulbaktama karşı, integron pozitif tüm P.aeruginosa suşlarında ise seftazidim, gentamisin ve siprofloksasine karşı ortak direnç paterni tespit edilmiştir. İntegronların DNA dizi analizleri, A.baumannii [aacC1-aadA1 ve aac(3)-1] ve P.aeruginosa (blaOXA-30-aadA1 ve blaOXA-11-cmlA7) suşlarının ikişer farklı gen kaset dizisi taşıdığını göstermiştir. Ulaşabildiği kadarıyla, P. aeruginosa integron gen kaseti içerisinde tanımlanan blaOXA-11-cmlA7 gen dizilimi ilk kez bu çalışma ile tanımlanmış ve yeni bir gen dizilimi olarak literatüre sunulmuştur.The dissemination of antibiotic resistance genes between bacteria leads to serious problems in the treatment of infectious diseases. It has been shown that resistance genes can also be carried by the inte- grons. There are limited studies regarding the carriage of class 1 and 2 integrons in Acinetobacter bau- mannii and Pseudomonas aeruginosa clinical strains in Turkey. The aims of this study were to investigate the carriage rates of class 1 and class 2 integrons in A.baumannii and P.aeruginosa strains isolated from clinical samples in Abant Izzet Baysal University Hospital, and to characterize the antibiotic resistance gene cassettes in these integrons by sequence analyses. A total of 137 strains (77 A.baumannii and 60 P.aeruginosa) isolated from various clinical specimens (56% were sputum, 19% wound, 11% urine, 11% blood, 3% catheter), between March 2010-December 2012, were included in the study. The identifica- tion and antibiotic susceptibility tests of the isolates were performed by Vitek 2 Compact (bioMérieux, France) and BD Phoenix 100 (Becton Dickinson, USA) systems. The presence of integrons were screened by PCR method using specific primer pairs targeting class 1 (intI1) and 2 (intI2) integrase regions. All the samples that revealed integron amplification were subjected to DNA sequence analysis, both in the forms of cloned products and PCR amplicons. In the study, the highest susceptibility rates were found against colistin (96%) and tigecycline (78%) in A.baumannii, and against piperacillin/tazobactam (97%) and piperacillin (93%) in P.aeruginosa isolates. The highest resistance rate was determined for piperacil- lin/tazobactam (95%) in A.baumannii strains. The presence of intI1 gene was detected in 33% (26/77) of A.baumannii and 10% (6/60) of P.aeruginosa isolates. When variable regions in intI1 positive strains were amplified by PCR, eight (8/77, 10%) A.baumannii and three (3/60, 5%) P.aeruginosa strains were found to harbor antibiotic resistance gene cassettes. IntI2 gene was not detected in any of the isolates. Resistance to piperacillin/tazobactam, ceftazidime, cefepime, ceftriaxone and ampicillin/sulbactam was detected as the common resistance pattern in all integron-positive A.baumannii strains, whereas resist- ance to ceftazidime, gentamicin and ciprofloxacin was the common pattern in all integron-positive P.aeruginosa strains. DNA sequence analysis of variable regions of integrons indicated that two separate gene cassette arrays (aacC1-aadA1 and aac(3)-1) were carried by A.baumannii strains, and two types of gene cassette arrays (blaOXA-30-aadA1 and blaOXA-11- cmlA7) were carried by P.aeruginosa strains. To our best knowledge, this is the first report of the gene sequence of blaOXA-11-cmlA7 defined in an integron gene cassette of P.aeruginosa

Detection Of The Frequency Of Per-1 Type Extended-Spectrum Β-Lactamase Producing Acinetobacter Baumannii Clinical İsolates İn Turkey: A Multicenter Study

Background/aim: β-Lactamases are an important resistance mechanism in Acinetobacter baumannii. Pseudomonas extended-resistance (PER-1) type β-lactamaseproducing strains have been reported from various geographic locations; however, PER-1 type β-lactamases from Turkish hospitals have not been investigated extensively. The aim of this study was to determine the prevalence of PER-1 type β-lactamases in A. baumannii isolates in various regions of Turkey. Materials and methods: A total of 763 clinical A. baumannii isolates were collected from 9 university hospitals and 2 state hospitals between 2008 and 2011. Molecular amplification of the OXA-51 gene from the A. baumannii genome was performed in order to verify identification of the species. Real-time polymerase chain reaction was used to detect blaPER-1 genes. Results: PER-1 was detected in 24.6% of the isolates. The annual frequencies of the PER-1 enzyme were detected as 52.2%, 35.9%, and 8.3% in 2008, 2009, and 2010, respectively. PER-1 prevalence decreased gradually over time. The differences observed in PER-1 prevalence among the regions of Turkey were statistically significant (chi-square test; P > 0.001). Conclusion: These data demonstrate that the frequency of detection of PER-1 type β-lactamases in A. baumannii species has decreased in Turkey. However, the increased carbapenem resistance, together with multidrug resistance, has created a worrisome situation regarding this pathogen

Carbapenem-resistant Klebsiella pneumoniae outbreak in a COVID-19 intensive care unit; a case-control study

We analysed a carbapenem-resistant Klebsiella pneumoniae (CRKP) outbreak in the coronavirus disease (COVID) ICU. We retrospectively collected data from ICU records. We identified 25 cases between 12 November 2020 and 19 December 2020, and compared them to 42 controls present in the ICU during the same period. The presence of a femoral haemodialysis catheter was strongly associated with invasive CRKP infections (cases, 9 [36%]; controls, 0 [0%]; odds ratio [OR] 95% confidence intervals [CIs], 21 (5; 89)). We found a significant association between old age and CRKP infection with adverse outcomes. Sequence analysis revealed three distinct carbapenemase genes: bla(NDM-1), bla(OXA-48) and bla(KPC-2). We launched rectal swab sampling upon admission to the ICU, cohorted colonized patients and cases and conducted an intensive training programme for newly employed staff. This study revealed that the emergence and dissemination of CRKP in COVID ICUs were associated with increased adverse outcomes. The presence of a femoral haemodialysis catheter was a significant risk factor for CRKP infections

Impact of antimicrobial drug restrictions on doctors' behaviors

Background/aim: Broad-spectrum antibiotics have become available for use only with the approval of infectious disease specialists (IDSs) since 2003 in Turkey. This study aimed to analyze the tendencies of doctors who are not disease specialists (non-IDSs) towards the restriction of antibiotics. Materials and methods: A questionnaire form was prepared, which included a total of 22 questions about the impact of antibiotic restriction (AR) policy, the role of IDSs in the restriction, and the perception of this change in antibiotic consumption. The questionnaire was completed by each participating physician. Results: A total of 1906 specialists from 20 cities in Turkey participated in the study. Of those who participated, 1271 (67.5%) had ≤5 years of occupational experience (junior specialists = JSs) and 942 (49.4%) of them were physicians. Specialists having >5 years of occupational experience in their branch expressed that they followed the antibiotic guidelines more strictly than the JSs (P < 0.05) and 755 of physicians (88%) and 720 of surgeons (84.6%) thought that the AR policy was necessary and useful (P < 0.05). Conclusion: This study indicated that the AR policy was supported by most of the specialists. Physicians supported this restriction policy more so than surgeons did.Background/aim: Broad-spectrum antibiotics have become available for use only with the approval of infectious disease specialists (IDSs) since 2003 in Turkey. This study aimed to analyze the tendencies of doctors who are not disease specialists (non-IDSs) towards the restriction of antibiotics. Materials and methods: A questionnaire form was prepared, which included a total of 22 questions about the impact of antibiotic restriction (AR) policy, the role of IDSs in the restriction, and the perception of this change in antibiotic consumption. The questionnaire was completed by each participating physician. Results: A total of 1906 specialists from 20 cities in Turkey participated in the study. Of those who participated, 1271 (67.5%) had ≤5 years of occupational experience (junior specialists = JSs) and 942 (49.4%) of them were physicians. Specialists having >5 years of occupational experience in their branch expressed that they followed the antibiotic guidelines more strictly than the JSs (P < 0.05) and 755 of physicians (88%) and 720 of surgeons (84.6%) thought that the AR policy was necessary and useful (P < 0.05). Conclusion: This study indicated that the AR policy was supported by most of the specialists. Physicians supported this restriction policy more so than surgeons did