Aerobacter Aerogenes, formerly known as Bacillus Aerogenes

Enterobacter Aerogenes, formerly known as Klebsiella Aerogenes

Enterobacter /En·tero·bac·ter/ (en´ter-o-bak?ter) a genus of gram-negative, facultatively anaerobic rod-shaped bacteria
of the family Enterobacteriaceae, widely distributed in nature and occurring in the intestinal tract of humans and animals.
Species including E. aero´genes, E. agglo´merans, E. cloa´cae, and E. gergo´viae, are frequently the cause of
nosocomial infection, arising from contaminated medical devices and personnel.


Enterobacter (a coliform & fecal coliform) is one of the Enterobacteriaceae. Infections include,
aneurysms, endocarditis, hospital infections, urinary tract and respiratory tract infections, necrotizing
enterocolitis "flesh eating". It is antibiotic resistant and now produces poisonous Hydrogen Sulfide
(H2S) gas.

In a 1981 study, “
Enteral feeds contaminated with Enterobacter cloacae as a cause of septicaemia,” M.
W. CASEWELL, et al., reported, “Artificial enteral feeds are increasingly used for patients with
severe catabolic states associated with, for example, bowel pathology, burns, infection, and malignancy.
One advantage claimed for using this route is the "virtual absence of the risk of infection."' Despite our
previous study which showed that contaminated enteral feeds were a source of Klebsiella spp for
intensive care patients,2 a recent Drugs and Therapeutics Bulletin on enteral feeding does not mention
the hazard of infection.3 We report on a patient with septicaemia caused by Enterobacter cloacae
derived from enteral feeds that had been contaminated by a detergent dispenser in a diet kitchen. – This
case illustrates how contaminated enteral feeds provide a source of opportunistic Gram-negative bacilli
that may colonise or seriously infect debilitated patients. Such organisms multiply readily at room
temperature, and there are thus advantages of using commercially produced bacteriologically clean
feeds, which do not require mixing with additives or diluents in the hospital environment, and
disadvantages of continuous infusion of mixed feeds over several hours at room temperature. We
suspect that other hospitals are similarly contaminating enteral feeds during their preparation and
suggest that the unsuspected, but avoidable, infection hazards of this common form of treatment
should be more widely recognised.”

In a 1987 study, “
Outbreak of cephalosporin resistant Enterobacter cloacae infection in a neonatal
intensive care unit,
” N. Modi, et al., reported, “Enterobacter cloacae resistant to third generation
cephalosporins emerged rapidly during an outbreak of serious infections due to this organism in a
neonatal intensive care unit where ampicillin and gentamicin were used as first line antibiotic
treatment. Organisms resistant to cephalosporins were isolated from 12 infants, six of whom developed
systemic infection. Two infants died. Isolates of E. cloacae from four of five infants treated with
cefotaxime showed a loss of sensitivity to this antibiotic during treatment, but in the three infants who
survived sensitive organisms were again isolated after treatment had stopped. Stopping treatment with
the cephalosporins, closure of the unit to new admissions, and strict cohorting of colonised infants
resulted in a prompt end to the outbreak. This outbreak suggests that the routine use of third generation
cephalosporins for suspected sepsis may be inappropriate in the presence of a large reservoir of
organisms with the potential for rapidly developing resistance. Routine bacteriological surveillance,
however, might permit their use on a rotational basis.” http://adc.bmj.com/content/62/2/148.abstract
In the 1998 study, “Occurrence of Virulence-Associated Properties in Enterobacter cloacae,” Rogéria
Keller, et al., Universidade Federal de São Paulo, reported, “Enterobacter cloacae is part of the normal
flora of the gastrointestinal tract of 40 to 80% of people and is widely distributed in the environment
(15, 19, 39). Like most members of the family Enterobacteriaceae, these organisms are capable of
causing opportunistic infections in hospitalized or debilitated patients (18, 19). They were recognized
as a minor cause of hospital infection in a survey published in 1981 (31). Since then, clinical awareness
of the potential of E. cloacae strains to cause disease has been reflected in the increasing number of
epidemiologic studies of these microorganisms showing that they could be a serious cause of
nosocomial gram-negative bacteremia (9, 17-19, 23).” http://iai.asm.org/cgi/content/full/66/2/645

In the 1999 study, “
Outbreak of Enterobacter cloacae Related to Understaffing, Overcrowding, and
Poor Hygiene Practices
,” Stephan Harbarth , MD, MS, et al., University Hospitals of Geneva, stated a
“Retrospective cohort study in a neonatal intensive‐care unit (NICU) from December 1996 to January
1997; environmental and laboratory investigations. – 60 infants hospitalized in the NICU during the
outbreak period. – Of eight case‐patients, two had bacteremia; one, pneumonia; one, soft‐tissue
infection; and four, respiratory colonization. – Several factors caused and aggravated this outbreak: (1)
introduction of E cloacae into the NICU, likely by two previously colonized infants; (2) further
transmission by HCWs’ hands, facilitated by substantial overcrowding and understaffing in the unit; (3)
possible contamination of multidose vials with E cloacae. Overcrowding and understaffing in periods
of increased work load may result in outbreaks of nosocomial infections and should be avoided.”

In a 2000 study, “
Detection of Extended-Spectrum -Lactamases in Clinical Isolates of Enterobacter
cloacae and Enterobacter aerogenes
,” Eva Tzelepi, et al., Hellenic Pasteur Institute at Athens, said,
“The aim of the present study was to investigate the frequency of extended-spectrum -lactamases
(ESBLs) in a consecutive collection of clinical isolates of Enterobacter spp. The abilities of various
screening methods to detect ESBLs in enterobacters were simultaneously tested. Among the 68
consecutive isolates (56 Enterobacter cloacae and 12 Enterobacter aerogenes isolates) that were
analyzed for -lactamase content, 21 (25 and 58%, respectively) possessed transferable ESBLs with pIs
of 8.2 and phenotypic characteristics of SHV-type enzymes, 8 (14.3%) of the E. cloacae isolates
produced a previously nondescribed, clavulanate-susceptible ESBL that exhibited a pI of 6.9 and that
conferred a ceftazidime resistance phenotype on Escherichia coli transconjugants, and 2 E. cloacae
isolates produced both of these enzymes. Among the total of 31 isolates that were considered ESBL
producers, the Vitek ESBL detection test was positive for 2 (6.5%) strains, and the conventional
double-disk synergy test (DDST) with amoxicillin-clavulanate and with expanded-spectrum
cephalosporins and aztreonam was positive for 5 (16%) strains. Modifications of the DDST consisting
of closer application of the disks (at 20 instead of 30 mm), the use of cefepime, and the use of both
modifications increased the sensitivity of this test to 71, 61, and 90%, respectively. Of the 37 isolates
for which isoelectric focusing failed to determine ESBLs, the Vitek test was false positive for 1 isolate
and the various forms of DDSTs were false-positive for 3 isolates.”

In a 2003 study, “
Nosocomial Enterobacter Meningitis: Risk Factors, Management, and Treatment
” Stephen Parodi, et al., Veterans Affairs Greater Los Angeles Healthcare System, reported,
“Enterobacter species are increasingly a cause of nosocomial meningitis among neurosurgery patients,
but risk factors for these infections are not well defined. A review of all adult patients hospitalized at
the University of California-Los Angeles (UCLA) Medical Center during an 8-year period identified 15
postneurosurgical cases of Enterobacter meningitis (EM). Cure was achieved in 14 cases (93%), and
efficacy was similar for carbapenem- and cephalosporin-based treatment. – Although uncommon, the
proportion of cases of nosocomial meningitis due to gram-negative organisms appears to be increasing
[1–3]. Appropriate empirical antimicrobial therapy for the treatment of gram-negative bacillary
meningitis is essential to prevent morbidity and mortality [3, 4], and treatment options are limited by
emerging resistance to third-generation cephalosporins, especially among Enterobacter species [5–7].”

In a 2010 Medscape article, “
Enterobacter Infections,” Susan L Fraser, MD, stated, “Enterobacter
species, particularly Enterobacter cloacae and Enterobacter aerogenes, are important nosocomial
pathogens responsible for various infections, including bacteremia, lower respiratory tract infections,
skin and soft-tissue infections, urinary tract infections (UTIs), endocarditis, intra-abdominal infections,
septic arthritis, osteomyelitis, and ophthalmic infections. Enterobacter species can also cause various
community-acquired infections, including UTIs, skin and soft-tissue infections, and wound infections,
among others. – These "ICU bugs" cause significant morbidity and mortality, and infection
management is complicated by resistance to multiple antibiotics.”

According to the Simon Fraser University, Brinkman Laboratory website at Vancouver, “Enterobacter
sakazakii ATCC BAA-894, …. primarily causes, Meningitis, septicemia, necrotizing enterocolitis.”

The 2011 Austin Community College Microbology for the Health Sciences report on “
," [states] Enterobacter bacteria are nosocomial opportunistic pathogens that cause infections that
~5% of hospital-acquired septicemias
~5% of nosocomial pneumonias
~4% of nosocomial urinary tract infections
~10% of postsurgical peritonitis cases
Some usefulness to humans, such as E. cloacae used in biological control of plant diseases.”

Enterobacter in Plants

In 1982, John M. Gardner, et al., University of Florida at Lake Alfred, reported on “Bacteria in Rough
Lemon Roots of Florida Citrus Trees.” They said, “An aseptic vacuum extraction technique was used to
obtain xylem fluid from the roots of rough lemon (Citrus jambhiri Lush.) rootstock of Florida citrus
trees. Bacteria were consistently isolated from vascular fluid of both healthy and young tree declineaffected
[dying] trees. Thirteen genera of bacteria were found, the most frequently occurring genera
being Pseudomonas (40%), Enterobacter (18%), Bacillus, Corynebacterium, and other gram-positive
bacteria (16%), and Serratia (6%). Xylem bacterial counts fluctuated seasonally. Bacterial populations
ranged from 0.1 to 22 per mm3 of root tissue (about 102 to 2 x 104 bacteria per g of xylem) when
bacterial counts were made on vascular fluid, but these numbers were 10- to 1,000-fold greater when
aseptically homogenized xylem tissue was examined similarly. Some of the resident bacteria (4%) are
potentially phytopathogenic. It is proposed that xylem bacteria have an important role in the physiology
of citrus.”

In the 1993 article, “
Enterobacter cloacae: internal yellowing of papaya (Plant Disease Pathogen),”
K.A. Nishijima, University of Hawaii, said, “Enterobacter cloacae has been isolated from papaya
flowers, homogenates of papaya seeds, and the crop and mid-gut of the oriental fruit fly (Dacus dorsalis
Hendel), and recent studies claiming an apparent attractancy of D. dorsalis to E. cloacae, suggest that
fruit flies may possibly be involved in the transmission of the bacterium to papaya. -- A report of E.
cloacae isolated from homogenates of papaya seeds in 1972 suggests that this organism may have been
present in a non-pathogenic form for many years. Monthly samplings from five papaya packinghouses,
that process fruit from different areas on the island of Hawaii, indicate that the incidence of internal
yellowing is sporadic and may be affected by environmental factors.”

In the Fall 2005 UMass Extension Landscape, Nursery & Urban Forestry Program, fact sheet,
Wetwood and slime flux” we find that a human pathogen also kills trees. Daniel H. Gillman, Plant
Pathologist said, “The bacteria Enterobacter cloacae along with several other bacteria commonly occur
in elms in association with the water-soaked condition of wood called bacterial wetwood. – Wetwood
and the bacteria consistently associated with it occur in nearly all elm (Ulmus) and poplar (Populus). In
addition, fir (Abies), hemlock (Tsuga), maple (Acer), mulberry (Morus), oak (Quercus), and white pine
(Pinus strobus) often have bacterial wetwood. – Wetwood occupies the trunk, branches, and roots of
affected trees. Most bacteria associated with wetwood commonly inhabit soil and water.”

Enterobacter: several species cause opportunistic infections of the urinary tract as well as other parts of the body.
E. aerogenes and E. cloacae are two such pathogens that do not cause diarrhea, but that are sometimes associated
with urinary tract and respiratory tract infections.

[PDF] Isolation and Identification of Enterobacter sakazakii in Infant ...File Format: PDF/Adobe Acrobat
Enterobacter sakazakii is a pathogen of increasing medical concern, due to it being implicated in cases of menin-. gitis,
sepis, and necrotizing ...
www.liebertonline.com/doi/abs/10.1089/fpd.2006.0071 - Similar pages

Causes: Meningitis, septicemia, necrotizing enterocolitis