Pulmonary Dysfunction Augmenting Bacterial Aerosols in Leather Tanneries of Punjab, Pakistan

Particulate matter-associated microbes in the workplace are a burning issue in occupational toxicology. Studies have reported on respiratory infections among tannery cohorts. This study uniquely presents measurements of airborne bacterial concentrations associated with varied particulate-matter sizes, their exposure, and consequent severity in occupational respiratory problems, all for different microenvironments within leather tanneries.

Analyses included molecular identification of isolates, computation of mass median aerodynamic diameter of aerosols, tannery process-exposure dose (TPED) to bacterial aerosols, and spirometry and symptom assessment of impaired pulmonary function.

The highest bacterial concentrations were for rawhide treatment and finishing units, showing 3.6×10³ and 3.7×10³ CFU/m³, respectively. Identified bacterial species included Ochrobactrum pseudogrignonense, Neisseria bacilliformis, Enterobacter cloacae, Alcaligenes faecalis, Klebsiella pneumoniae, and Corynebacterium spp. Maximum and minimum values of mass median aerodynamic diameter were 8.3 µm and 0.65 µm for buffing and snuffing and production units, respectively. The highest TPED was 1,516.9 CFU/kg for finishing units. Respiratory symptoms in order of incidence were dyspnea > phlegm > cough > wheezing and tachypnea (equivalent). Bronchodilator measurements of FEV₁, FVC, and PEF represent decline in lung function. Of 26 patients identified with COPD, most were working in rawhide treatment.

We conclude that exposure-infection synergy is also a cause of pulmonary ailments and COPD development, rather than the better-known exposure-smoking synergy.