Clonal diversity and detection of carbapenem resistance encoding genes among multidrug-resistant Acinetobacter baumannii isolates recovered from patients and environment in two intensive care units in a Moroccan hospital

Background Carbapenem-resistant Acinetobacter baumannii has recently been defined by the World Health Organization as a critical pathogen. The aim of this study was to compare clonal diversity and carbapenemase-encoding genes of A. baumannii isolates collected from colonized or infected patients and hospital environment in two intensive care units (ICUs) in Morocco. Methods The patient and environmental sampling was carried out in the medical and surgical ICUs of Mohammed V Military teaching hospital from March to August 2015. All A. baumannii isolates recovered from clinical and environmental samples, were identified using routine microbiological techniques and Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry. Antimicrobial susceptibility testing was performed using disc diffusion method. The carbapenemase-encoding genes were screened for by PCR. Clonal relatedness was analyzed by digestion of the DNA with low frequency restriction enzymes and pulsed field gel electrophoresis (PFGE) and the multi locus sequence typing (MLST) was performed on two selected isolates from two major pulsotypes. Results A total of 83 multidrug-resistant A. baumannii isolates were collected: 47 clinical isolates and 36 environmental isolates. All isolates were positive for the bla OXA51-like and bla OXA23-like genes. The coexistence of bla NDM-1 /bla OXA-23-like and bla OXA 24-like /bla OXA-23-like were detected in 27 (32.5%) and 2 (2.4%) of A. baumannii isolates, respectively. The environmental samples and the fecally-colonized patients were significantly identified (p < 0.05) as the most common sites of isolation of NDM-1-harboring isolates. PFGE grouped all isolates into 9 distinct clusters with two major groups (0007 and 0008) containing up to 59% of the isolates. The pulsotype 0008 corresponds to sequence type (ST) 195 while pulsotype 0007 corresponds to ST 1089.The genetic similarity between the clinical and environmental isolates was observed in 80/83 = 96.4% of all isolates, belonging to 7 pulsotypes. Conclusion This study shows that the clonal spread of environmental A. baumannii isolates is related to that of clinical isolates recovered from colonized or infected patients, being both associated with a high prevalence of the bla OXA23-like and bla NDM-1genes. These findings emphasize the need for prioritizing the bio-cleaning of the hospital environment to control and prevent the dissemination of A. baumannii clonal lineages

First reported nosocomial outbreak of Serratia marcescens harboring blaIMP-4 and blaVIM-2 in a neonatal intensive care unit in Cairo, Egypt

Doaa Mohammad Ghaith,1 Mai Mahmoud Zafer,2 Dalia Kadry Ismail,1 Mohamed Hamed Al-Agamy,3,4 Marie Fe F Bohol,5 Ahmed Al-Qahtani,5 Mohammed N Al-Ahdal,5 Sherif M Elnagdy,6 Islam Yousif Mostafa7 1Department of Clinical and Chemical Pathology, Faculty of Medicine, Cairo University, Cairo, Egypt; 2Department of Microbiology and Immunology, Faculty of Pharmacy, Ahram Canadian University, Giza, Egypt; 3Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia; 4Department of Microbiology and Immunology, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt; 5Department of Infection and Immunity, Research Center, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia; 6Department of Botany and Microbiology, Faculty of Science, Cairo University, Cairo, Egypt; 7Department of Microbiology, Faculty of Dentistry and Oral Medicine, Future University, Cairo, Egypt Introduction: Serratia marcescens is a significant hospital-acquired pathogen, and many outbreaks of S. marcescens infection have been reported in neonates. We report a sudden breakout of&nbsp;S. marcescens&nbsp;harboring the blaIMP-4 and&nbsp;blaVIM-2 metallo-&beta;-lactamase (MBL) genes that occurred from March to August 2015 in the neonatal intensive care unit of Cairo University Hospital, Cairo, Egypt. Methods: During the study period, 40 nonduplicate clinical isolates of&nbsp;S. marcescens&nbsp;were collected from blood culture samples. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used to identify each isolate. Then, minimum inhibitory concentrations of different antibiotics were assessed by the Vitek 2 compact system. Screening of the MBL genes blaIMP,&nbsp;blaVIM,&nbsp;blaSIM-1,&nbsp;blaSPM-1, and&nbsp;blaGIM-1 as well as the carbapenemase genes KPC, NDM, OXA-48, SME-1, and SME-2 were evaluated. Pulsed field gel electrophoresis was preformed to detect the genetic relationship of the isolates. Results: Analysis showed that 37.5% of the S. marcescens clinical isolates were resistant to meropenem (minimum inhibitory concentrations &ge; 2 &micro;g/mL), and&nbsp;blaIMP-4&nbsp;and&nbsp;blaVIM-2 were the most prevalent MBL genes (42.5% and 37.5%, respectively). None of the other investigated genes were observed. Pulsed field gel electrophoresis typing revealed two discrete clones; 33/40 (82.5%) were pulsotype A and 7/40 (17.5%) were pulsotype B. Conclusion: Here, we report for the first time the detection of MBL-producing&nbsp;S. marcescens&nbsp;isolates, particularly IMP-4 and VIM-2 recovered from inpatients with bacteremias from the intensive care unit at Cairo University Hospital. Keywords: PFGE, outbreak, MALDI-TOFF, SME-1, SME-2, carbapenemases, MBL gene