Epidemiology of Klebsiella Pneumoniae Infection in Four Specialist Health Institutions in Enugu Urban, Enugu State, Nigeria.


In a comprehensive study conducted to determine the epidemiology of Klebsiella pneumoniae infection in four specialist health institutions in Enugu urban of Enugu State, Nigeria, a total of 564 cases were enlisted which involved 298 (52.8%) patients on admission in the hospitals, and 266 (47.2%) outpatients, aged 1 to 80 years. The study was carried out from October 2012 to March 2014.

Sample collections for the study were based on the doctors’ assumption of diagnosis (from patients whose complaints were mainly suggestive of respiratory tract infection, urinary tract infection, bactereamia, meningitis, liver ascitis, diabetes and wound sepsis). Different specimens were collected from the patients (midstream urine, sputum and lung aspirates, blood, ascitic fluid, cerebrospinal fluid and wound swabs) and cultured in appropriate media.

The isolates were identified by conventional methods. Extended spectrum beta-lactamase production was screened using Double Disc Synergy Test method (DDST). Plasmid elimination was done using the method of Stanisich. A total of 29 (5.1%) of Klebsiella pneumoniae was isolated from the 564 samples analysed. Urinary tract infection constituted 22 (75.9%), respiratory tract infection 4 (13.8%), wound sepsis 2 (6.9%) while bacteraemia/liver ascites was 1(3.5%).

The number of male isolates were 12 (41.4%) a little bit smaller than that of female isolates 17 (58.6%). This was found not to be statistically significant (p > 0.05). The incidence of Klebsiella pneumoniae from non-hospitalized patients were 10 (34.5%), while hospitalized patients constituted 19 (65.5%) which difference was statistically significant (p<0.05). 


Epidemiology is a broad topic, meaning differently to people according to discipline. For a medical epidemiologist, it is a study of the distribution and frequency of infection and diseases on the population level with the aim to identify the factors responsible for the observed patterns, to make prediction and develop vaccination programme (Barbara, 1997). By identifying the cause of disease, epidemiology has prompted advances in medicine and better ways of controlling and preventing diseases (Hanford, 2005).

The genus Klebsiella belongs to the tribe Klebsiellae, a member of the family Enterobacteriaceae. The organism is named after Edwin Klebs, a 19th century German microbiologist (Obiamiwe et al., 2011). Klebsiellae are non-motile, rod-shaped, Gram negative bacteria with a prominent polysaccharide capsule. This capsule encases the entire cell surface, account for the larger appearance of the organism on Gram stain, and provides resistance against many host defense mechanisms.

Klebsiella is one of the enterobacteriaceae that are usually encapsulated (the others are Enterobacter aerogenes and Enterobacter cloacae which produces small capsule but motile at 360 C) (Podschun and Ullamns, 1998). Members of the Klebsiella genus typically express 2 types of antigen on their cell surface. The first is a lipopolysaccharide (LPS) (O antigen); the other is a capsular polysaccharide (K antigen). Both of these antigens contribute to pathogenicity. About 77 k antigens and 9 O- antigens exist.

The structural variability of these antigens forms the basis for classification into various serotypes. The virulence of all serotypes appears to be similar (Ningthoujam, 2008). The genus Klebsiella is currently grouped into 7 species with demonstrated similarities in DNA homology known. These are (1) Klebsiella pneumoniae, (2) Klebsiella ozaenae, (3) Klebsiella rhinoscleromatis, (4) Klebsiella oxytoca, (5) Klebsiella planticola, (6) Klebsiella terrigena and (7) Klebsiella ornithinolytica.


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