Distribution and Antibiotic Resistance of Klebsiella Species in the Aquatic Environment

Klebsiella is a genus of gram-negative bacteria that is member of the Enterobacteriacea. There are seven species of Klebsiella, of these K. pneumoniae, K. oxytoca and K. rhinoscleromatis have been found in human clinical specimens. K. pneumoniae and K. oxytoca account for eight percent of nosocomial infections in the United States and Europe. K. pneumoniae has a worldwide distribution and is an important cause of community-acquired pneumonia in elderly persons. In the United States the mortality rate is as high as 50% even with antimicrobial therapy. K. oxytoca is the second most frequent cause of gram-negative neonatal bacterium and is among the top four pathogens that cause infection in patients in neonatal intensive care units. The purpose of our study is to identify the species distribution of Klebsiella in the aquatic environment and to discern the resistance profiles of the species observed. We collected water from various aquatic environments including seawater, fresh water and ice water within Southern California. Using matrix assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry we identified 33 isolates of K. pneumonia and 7 isolates of K oxytoca. The resistance profiles of the Klebsiella isolates were obtained using the Disk Suseptibility Test, following Clinical and Laboratory Standards Insitiute (CLSI) guidelines. It was found that most of the resistance came from the K. pnuemoniae species. Its resistance profile was as follows: 100% resistant to Ampicillin, 82% to Nitrofurantoin, 91% to Piperacillin, 20% to Sulfamethoxazole Trimethprime, 76% to Amoxicillin Clavulanic Acid, 3% to Amikacin, Ceftazidime, Cefepmine, Gentamicin, and Ciprofloxacin. K. oxytca showed 100% resistance to Ampicillin and 25% resistance to Piperacillin. Within the K. pnuemoniae species, 47% of the isolates came from seawater, 41% from fresh water and 13% from ice water. In K. oxytoca 29% came from seawater, 43% from ice water, and 29% from fresh water. The two most common species found were K. pnuemoniae and K. oxytoca, with K. pnuemoniae contirbuting most to resistance. It also illustrates K. pnuemoniae was mostly found in sea and fresh water whereas K. oxytoca was mostly found in ice water. Supported by MBRS NIH Grant GM055246.