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EXPOSURE OF WORKERS TO AIRBORNE
MICROORGANISMS DURING CLEANING OF PIGEON
FAECES POLLUTED BUILDINGS
P. Kämpfer*, U. Jäckel and A. Albrecht
Institut für Angewandte Mikrobiologie, Justus-Liebig-Universität Giessen,
Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany.
E-mail: peter.kaempfer@agrar.uni-giessen.de
Abstract
During cleaning procedures in rooms contaminated with pigeon faeces, extensive dust contaminated with various microorganisms can be aerosolised. In this study levels of airborne microorganisms were quantified and partly identified. Airborne culturable bacteria were collected using filtration samplers and impingers. The concentrations of airborne microorganisms on CASO and DG18
7-3agar were generally high, up to 10 CFU m air. Concentrations of representatives
3-3of Enterobacteriaceae were often found in a range of 10 CFU m air. Highest
concentrations were found in aerosols from fresh faeces. The amount of bacteria decreased with the age of the faeces. The same tendency was found for Campylobacter and yeast numbers. In general, the concentrations of thermophilic fungi were low. Chlamydophila psittaci was detected only in some bioaerosols
originated from fresh faeces.
INTRODUCTION
Extensive accumulations of pigeon faeces is often observed in areas where these birds occur in large numbers. Pigeon faeces contains various clinically relevant bacteria, among them Chlamydophila psittaci, Campylobacter spp.,
Salmonella spp. and yeasts like Cryptococcus neoformans. During cleaning
procedures these organisms can be aerosolized and hence can be inhaled by workers. Therefore, employees who are cleaning, restoring or repairing bridges, fronts of buildings or lofts are often exposed to these microorganisms.
In a two year study the levels of airborne microorganisms in different buildings were quantified and partly identified during specific working conditions in order to make a risk assessment.
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MATERIALS AND METHODS
Airborne culturable microorganisms were collected at a height of 1.5 m during specific cleaning conditions using three sampling methods: filtration with
-1MD8 air-sampler (Sartorius, Göttingen, Germany) operated at 100 l min for 10
min and gelatine membrane filter (pore size 3.0 µm); filtration with personal air
-1sampler PGP-GSP (GSA Messgerätebau, Neuss, Germany) operated at 3.5 l min
for 30 min and gelatine membrane filter (pore size 3.0 µm); and liquid impingement with an all-glass impinger (AGI) with 30-mm jet-to-bottom spacing
-1(AGI-30; Zinsser Analytic, Frankfurt, Germany) operated at 12.7 l min for 30 min,
each filled with 50 ml of sterile 0.9% w/v NaCl-solution. All samples were analysed within 24 hr according to a standardize bioaerosol collection method of a committee of the German Ministry of Labour (Technical standard TRBA 430). For indirect processing, each of the filters were dissolved in 10 ml of 0.9% NaCl-solution, containing 0.01% Tween-80 at pH 7. Impinger solutions could be used directly. For homogenisation the solutions were shaken for 15 min at 35 ?C until they became clear. After serial dilutions, selective agars for Enterobacteriaceae
(Salmonella-Shigella- and MacConkey No.3, both incubated at 36 ?C),
(Campylobacter-selective-agar, incubated at 36 ?C by using Campylobacter
;Anaerocult for reduction of O and enrichment of CO), thermophilic moulds 22
(malt-extract with chloramphenicol and oxytetracycline, incubated at 45 ?C),
xerophilic moulds (Dichloran-Glycerol (DG 18) with chloramphenicol and
oxytetracycline, incubated at 25 ?C), yeasts (Sabouraud, incubated at 36 ?C), and
"total counts" (CASO, incubated at 36 ?C) were inoculated in three replicates with 0.1 ml. Numbers of grown colonies were counted and concentrations of microorganisms were calculated as a mean of the three replicates as colony-
-3forming units (cfu) m air.
Selected samples were studied for the presence of Chlamydophila.
Suspensions were inoculated to tissue cultures (BGM-Nonlayer), transferred and subsequently investigated in a fluorescence microscope with genus-specific monoclonal FITC-marked antibodies. In addition, the presence of Chlamydophila
DNA was studied using multiplex-PCR. psittaci-
RESULTS AND DISCUSSION
The results obtained for three of eight working places are shown in Figures 1 to 3. Overall the following highest concentrations of airborne microorganisms
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-3773were measured [ranges of cfu m]: CASO: 10; DG-18: 10; maltextract: 10; SS:
543410; MacConkey: 10; Campylobacter: 10; Sabouraud: 10. Generally,
concentrations of airborne microorganisms on CASO and DG-18 agar were high. Concentrations of representatives of Enterobacteriaceae were often found in a
3-3range of 10 CFU m air. These gram-negative bacteria are very sensitive to environmental conditions so it is not surprising to find their highest concentrations in aerosols from fresh faeces. Therefore, the amount of bacteria decreased with the age of the faeces. The same tendency was found for Campylobacter and yeast numbers. Concentrations of thermophilic fungi were generally low. The replication of thermophilic organisms depends on temperatures over 40 ?C which could not be expected in the examined buildings of this study. Chlamydophila psittaci was detected only in some bioaerosols
originated from fresh faeces. The very high concentrations on a loft measured 9 month after cleaning (fig. 1) were remarkable. This results show, that even after a deposition of some month microorganisms can occur in relevant amounts.
Bacteria cultivated on MacConkey- and Salmonella-Shigella-agar were mainly assigned to risk group 2 and avian strains of Chlamydophila psittaci in risk
group 3. Dependent on extent and age of pollution as well as type of the cleaning process there is a potential endangering of man. Besides usual hygiene we recommend specific personal safety equipment including breathing mask.
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1,00E+08
1,00E+07
1,00E+06
1,00E+05 air-3
1,00E+04
CFU m1,00E+03
1,00E+02
1,00E+01
1,00E+00
MacConkeySSSabouraudCampylobacterDG18MaltCaSo
36363636254536means
after cleaning [h]:medium / temperature [癈]Xmedian0,5 1,5 23
Figure 1. Concentrations of airborne microorganisms measured during simulated cleaning
procedures on a loft. At the beginning of redevelopment faeces, nests, plumes and carcasses of pigeons were found. There were no pigeons on the loft for 9 month between cleaning and measurement. Shown are means, medians and concentrations at different times after the cleaning. Chl. psittaci was detected in 2 of 8 samples.
1,00E+08
1,00E+07
1,00E+06
1,00E+05 air-31,00E+04
1,00E+03CFU m
1,00E+02
1,00E+01
1,00E+00SSMacConkeyMaltCaSoSabouraudDG18363645363625
medianmeanmedium / temperature [癈]
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Figure 2. Concentrations of airborne microorganisms measured during cleaning procedures in a closed room under a bridge. At the beginning of cleaning there were a lot of pigeons, nests, eggs, plumes, carcasses and skeletons inside. The floor was covered with Faeces in a high of 10 cm. Cleaning was done by using broom and shovel. Shown are
highest concentrations of 20 samples, means and medians. Chl. psittaci was detected in 3
of 5 samples.
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1,00E+08
1,00E+07
1,00E+06
1,00E+05 air-3 1,00E+04
CFU m1,00E+03 1,00E+02
1,00E+01
1,00E+00 MacConkeyDG18MaltCaSoSSSabouraudCampylobacter
36254536363636 mean medium / temperature [?C]median
Figure 3. Concentrations of airborne microorganisms measured during cleaning procedures on a loft with broom and shovel. The floor was covered with faeces in an high of 1-2 cm. At the beginning of cleaning there were some pigeons inside. Chl. psittaci was
detected in none of 4 samples.
Acknowledgement
The investigations were supported by the Tiefbau-Berufsgenossenschaft,
Munich, Germany.
REFERENCES
TRBA - Technische Regel für Biologische Arbeitsstoffe 430 "Verfahren zur Bestimmung der Schimmelpilzkonzentration in der Luft am Arbeitsplatz". Bundesarbeitsblatt (2001), 8, S. 79-83.