| dc.description.abstract | Investigations have revealed Large microbial populations in
many hatcheries despite the application of various sanitary
measures.Many of the pathogenic organisms which affect the
eggs, embryos and hatched chicks may be air-borne, egg-borne or
may be from residual hatcher contamination. The degree of
contamination has been measured by microbial examination of
hatcher fluff, air sampling techniques, and by surface sampling;
a systematic approach to hatchery sanitation depends on the
elucidation of the principal sources of hatcher contamination.
This study was aimed at isolating and identifying the types of
pathogenic bacteria that cause mortality in hatching chicks, and
determining their sources of reservoirs within hatcheries with a
view to controlling them.
The best samples were obtained from three hatcheries in
Kenya, and from numerous poultry farms in and around Nairobi.
The samples included eggs, dead-in-shells, sick and dying
chicks, water, fluff, hatcher debris, and swabs from hatchery
surfaces and hands of hatchery personnel. All samples were
initially processed to produce appropriate inocula and cultured
on MacConkey agar, Blood agar and Nutrient agar media for
primary isolation. Fluids were inoculated directly onto culture
media. Bacterial isolates were later inoculated onto
characterisation media and biochemical preparations for
identification. Purified bacterial isolates were subsequently
preserved and later subjected to antibiolic and disinfectant
susceptibility tests. Swabbing for total bacterial counts was
made before and after application of fumigants and disinfectants
to determine the sanitary status of the hatcheries.
A total of 567 bacterial isolates covering over 18 genera
and over 43 species was made. Of these, 237 isolates were
recovered from hatchery machines and fluff and hatcher debris
samples, 174 were from hatchery environment including water, air
and hands of personnel, and 156 isolates were recovered from
dead-in-shalls and from sick and dying chicks. The top ten most
frequently isolated genera were bacillus(18.5%),
Staphylococcus (17.5%),Pseudomonas(14.5%),Streptococcus
(13.2%),escherichia(12.3%),Proteus(4.6%),Diploccus
(4.2%), enterobacter(3.7%),Citrobacter(2.6%) and Klebsiella
(1.9%). Of these, the top ten isolated from dying chicks and
unhatched/incubating eggs were, in decreasing order, escherichia,Streptococcus,Staphylococcus,Proteus,Pseudomonas,bacillus, Klebsiella,enterobacter,Citrobacter and pastereulla.
Two hundred and forty three of the isolates were tested
against 7 disinfectants commonly used in Kenya. At the
manufacturers' use-dilution, the percent kill was 97 for
Bromosept(R), 60 for Lysol(R), 47 for Pynol-S(R), 40 for
Rhino(R) disinfectant, 31 for Biodan(R), 7 for Kerol(R)
and 0 (zero) for Municipal fluid(R)-. Whereas the
Bromosept(R), Biodan(R) and Lysol(R) had broad spectrum
activity,Pynol-5(R) ,Kerol(R) and Rhino(R) -disinfectants
had effect mainly on G+ve bacteria only.
Two hundred and sixty five of the isolates were tested
against 13 antibiotics. Multiple antibiotic resistance was
demonstrated mainly among members of escherichia,Streptococcus,Pseudomonas,Proteus,Citrobacter,Staphylococcus and Klebsiella in a decreasing order. The multiple resistance pattern was 25% to
3 antibiotics,19%to 4, 26% to 5, 15% to 6, 6% to 7 and 9% to 8
and over antibiotics. The top seven showing the most broad
spectrum of activity were, in decreasing percentage, Kanamycin
(100), Gentamicin (96), Cotrimoxazole (85), Nitrofurantoin (85),
Ampicillin (82), Tetracycline (80) and Chloramphenicol (78%).
Also demonstrated was existence of resistance to both
antibiotics and disinfectants among many bacterial isolates, the
top 7 of which were echerichia(71%), Citrobacter(64%),
Proteus(60%),Klebsiella(60%),Pseudomonas(50%),
enterobacter(14%) and Streptococcus(14%).
The conclusions reached were that swabbing recovered a very
small percentage of the bacteria on the surfaces, and that
applications of fumigants and disinfectants on surfaces always
left behind some bacteria resistant to these agents. The most
frequent bacteria isolated from chicles and egs, e. coli. was
also the one showing the highest pattern of multiple resistance
to both antibiotics and disinfectants. The disinfectants tested
were not effective for general purpose disinfection at the
manufacturers' use - dilution except Lysol(R) and
Bromosept(R). In-the-field tests for disinfectant efficacy
should be carried out in a manner similar to the more routine in
vitro antibiotic sensitivity tests before a choice of agent for
general purpose disinfection is made. | en |
