Abstract
Gram-negative bacilli (GNB) cause many cases of pneumonia in Indonesia. We investigated nasopharyngeal carriage of GNB in Semarang, Indonesia. Klebsiella pneumoniae carriage in adults (15%) was higher than in children (7%) (P = 0.004), while that of other GNB was comparable. Poor food and water hygiene are determinants of carriage of these bacteria.
TEXT
Worldwide, Streptococcus pneumoniae is the most common cause of community-acquired pneumonia (CAP). However, in low-to-middle-income countries, Gram-negative bacilli (GNB) are reported as frequent causes of CAP (1). In a recent study on CAP in Indonesia, Klebsiella pneumoniae was the most common etiological agent (our unpublished observation). Since nasopharyngeal colonization may precede pneumonia, as for S. pneumoniae (2), we investigated nasopharyngeal carriage of K. pneumoniae and other GNB among children and adults compared to that of S. pneumoniae in Indonesia. Subjects were healthy children (6 to 60 months old) and adults (45 to 70 years old) living in the city of Semarang on the island of Java in Indonesia, without respiratory symptoms and without antibiotic consumption within the last 3 days. Subjects were recruited from all 16 districts of Semarang by cluster random sampling from February to April 2010.
Nasopharyngeal swabs were obtained and transported in Amies (COPAN, Italy) and then were inoculated on 5% sheep blood agar with gentamicin (5 mg/liter) and on MacConkey agar. The plates were incubated at 35°C in 5% CO2. Identification and antimicrobial susceptibility tests for GNB were performed using Vitek 2 (bioMérieux, Marcy l'Etoile, France). Identification of S. pneumoniae was performed using the optochin test (Oxoid, Basingstoke, United Kingdom). Control strains were included, and CLSI guidelines were applied.
A questionnaire was developed to identify determinants of carriage of these bacteria. Data on demography, water supply (for drinking, preparing food, and bathing), food hygiene and house sanitation (crowding, flies, and exposure to smoke from cigarettes and mosquito coils), were collected. Water hygiene was considered poor when water other than tap water or bottled water was used. Food hygiene was considered poor if food was bought from street vendors. Crowding was considered if the ratio of bedroom space per family member was <4 m2 (3). Univariate analysis was done with chi-square or Fisher's exact test when appropriate, followed by logistic regression using SPSS 17 (SPSS Inc., Chicago, IL, USA). Confidence interval (CI) was calculated at the 95% level (CI95), and P values of <0.05 were considered significant. Written informed consent was obtained from the subjects or their caregivers. The study was approved by the Ethical Committee of the Faculty of Medicine, Diponegoro University.
A total of 253 adults and 243 children participated in the study; approximately 25% resided in the suburbs, and the majority were living under hygienically restricted circumstances regarding their food and water supplies. Crowding and exposure to smoke were common (Table 1).
Table 1.
Characteristics of the study participants
| Characteristic | No. (%) of subjects with this characteristic, unless specified otherwise |
P valuea | ||
|---|---|---|---|---|
| Children | Adults | All subjects | ||
| Gender | ||||
| Male | 118 (49) | 94 (37) | 212 (43) | 0.01 |
| Female | 125 (51) | 159 (63) | 284 (57) | |
| Age (yr) | ||||
| Median | 2.1 | 55 | ||
| Range | 0.5–5 | 45–75 | ||
| Residence | ||||
| Urban | 180 (74) | 186 (74) | 366 (74) | 0.9 |
| Suburban | 63 (26) | 67 (26) | 130 (26) | |
| Food hygiene | ||||
| Good | 81 (33) | 107 (42) | 188 (38) | 0.04 |
| Poor | 162 (67) | 146 (58) | 308 (62) | |
| Water hygiene | ||||
| Good | 114 (47) | 119 (47) | 233 (47) | 0.9 |
| Poor | 129 (53) | 134 (53) | 263 (53) | |
| Crowdingb | ||||
| No | 129 (56) | 157 (66) | 286 (61) | 0.03 |
| Yes | 100 (44) | 80 (34) | 180 (39) | |
| Mosquito coil use | ||||
| No | 184 (76) | 170 (67) | 354 (73) | 0.04 |
| Yes | 59 (24) | 83 (33) | 142 (29) | |
| Active smoking | ||||
| No | 243 (100) | 200 (79) | 443 (89) | 0.01 |
| Yes | 0 (0) | 53 (21) | 53 (11) | |
| Passive smoking | ||||
| No | 97 (40) | 106 (42) | 203 (41) | 0.7 |
| Yes | 146 (60) | 147 (58) | 293 (59) | |
| Contact with toddler(s) | ||||
| No | 111 (46) | 116 (46) | 227 (46) | 0.9 |
| Yes | 132 (54) | 137 (54) | 269 (54) | |
| Total no. | 243 | 253 | 496 | |
The P values are comparing the distributions of the variables for children versus adults.
Only 366 subjects responded to this question.
The carriage rate of K. pneumoniae and other GNB was 11% (CI95, 7 to 14%) and 19% (CI95, 12 to 23%), respectively. K. pneumoniae carriage in adults (15%) was higher than in children (7%) (P = 0.004), while that of other GNB was comparable (Table 2). Carriage of S. pneumoniae was 43% in children and 11% in adults (P = 0.000). Combined carriage of these bacteria was common. The presence or absence of one species was not significantly correlated to that of the other species (P > 0.1). The prevalence of carriage of these bacteria varied significantly by city districts and tended to be higher in the suburban and eastern parts of the city.
Table 2.
Distribution of nasopharyngeal colonization among young children and adults in Semarang, Java, Indonesia
a GNB, Gram-negative bacilli.
Fifty-four K. pneumoniae strains were isolated from 54 subjects. One isolate was resistant to cefotaxime and ceftriaxone, but the presence of an extended-spectrum beta-lactamase could not be confirmed. The remaining strains were susceptible to common antibiotics, including cefuroxime, but excluding nitrofurantoin (43% resistant).
One-hundred seven GNB strains other than K. pneumoniae were found in 96 (19%) subjects (49 children and 47 adults). The three most frequently isolated genera were Pseudomonas, Enterobacter, and Acinetobacter (Table 3). All members of the family Enterobacteriaceae other than K. pneumoniae were susceptible to carbapenem, and 95% of the strains were susceptible to piperacillin-tazobactam, expanded-spectrum cephalosporins, gentamicin, meropenem, and ciprofloxacin. All Pseudomonas isolates were susceptible to tobramycin, meropenem, and ciprofloxacin, 67% were susceptible to ceftazidime, and 87% were susceptible to colistin.
Table 3.
Nasopharyngeal carriage of Gram-negative bacilli
| Species | No. (%) of subjects carrying the indicated species |
||
|---|---|---|---|
| Children (n = 243) | Adults (n = 253) | All subjects (n = 496) | |
| K. pneumoniae | 16 (7) | 38 (15) | 54 (11) |
| Other GNBa | 56 (23) | 51 (20) | 107 (21) |
| Pseudomonas spp. | 16 (7) | 9 (4) | 25 (5) |
| Enterobacter spp. | 11 (5) | 10 (4) | 21 (4) |
| A. baumannii comp.b | 11 (5) | 3 (1) | 14 (3) |
| Citrobacter spp. | 0 (0) | 11 (4) | 11 (2) |
| Aeromonas spp. | 6 (2) | 3 (1) | 9 (2) |
| Pantoea spp. | 6 (2) | 3 (1) | 9 (2) |
| Serratia spp. | 0 (0) | 4 (2) | 4 (1) |
| Escherichia coli | 0 (0) | 3 (1) | 3 (1) |
| Stenotrophomonas maltophilia | 1 (1) | 1 (1) | 2 (1) |
| Other non-lactose-fermenting bacillic | 5 (2) | 4 (2) | 9 (2) |
| Total carriage of GNB | 72 (30) | 89 (35) | 161 (32) |
GNB, Gram-negative bacilli.
Acinetobacter baumannii complex.
Other nonfermenting bacilli were Comamonas testosteroni, Leclercia adecarboxylata, Rhizobium radiobacter, Proteus vulgaris, Brucella melitensis, Shewanella algae, and Sphingobacterium spiritivorum.
Multivariate analysis showed that being an adult (odds ratio [OR], 2.2; CI95, 1.1 to 4.2), having poor water hygiene (OR, 2.1; CI95, 1.1 to 3.9), having poor food hygiene (OR, 2.2; CI95, 1.1 to 4.3), and using mosquito coils (OR, 1.8; CI95, 1.1 to 4.3) were independent determinants of K. pneumoniae nasopharyngeal carriage. Poor water hygiene (OR, 1.8; CI95, 1.1 to 2.9), poor food hygiene (OR, 1.8; CI95, 1.1 to 2.7) and being a female (OR, 1.9; CI95, 1.2 to 3.1) were independent determinants of other GNB carriage.
This is the first population-based study of nasopharyngeal carriage of GNB in Indonesia. The carriage rate of GNB exceeded that of S. pneumoniae in adults. Overall, 30% of the participants carried GNB. K. pneumoniae was the commonest GNB species carried, significantly higher among adults than among children. Few publications are available regarding nasopharyngeal carriage of K. pneumoniae or GNB. These bacteria are not considered commensals in the nasopharynxes of healthy individuals. K. pneumoniae and other GNB throat carriage is found in specific conditions, such as preceding antibiotic therapy, underlying diseases, or long hospital stay (4). A study in Brazil, a high middle-income country (World Bank 2011) found a 9% carriage rate of GNB among 1,192 children attending day care, with K. pneumoniae in only 1.4% of the children (5). We showed that carriage of K. pneumoniae and other GNB in healthy individuals in Semarang, Indonesia, is much more common and related to poor hygiene, particularly water and food hygiene.
K. pneumoniae and other GNB are present in the enteric microflora which may serve as a source of water contamination particularly in countries with poor sanitation (6). People who use contaminated water could, thus, become colonized. Food preparation using contaminated water may increase the risk of transmission to the nasopharynx. A study in neighboring Malaysia found that 32% of street food contained K. pneumoniae (7).
Using mosquito coils was also a K. pneumoniae carriage determinant. It has been demonstrated that one mosquito coil releases the same amount of particulate matter as 75 to 137 cigarettes (8).
Carriage of K. pneumoniae and other GNB may play a role in the pathogenesis of pneumonia in this part of the world (1), but this hypothesis requires further study. Importantly, in this respect, almost all K. pneumoniae strains were found to have the wild-type susceptibility to common antimicrobial agents, similar to those found in CAP patients in Semarang, Indonesia (our unpublished observation). This finding confirms previous reports from the same community, where acquired resistance was rarely found among enteric bacilli isolated from healthy people (9, 10).
In conclusion, nasopharyngeal carriage of K. pneumoniae and other GNB is common among healthy people in Indonesia and is caused in part by exposure to unsafe water and food.
ACKNOWLEDGMENTS
We thank medical students from the Faculty of Medicine of Diponegoro University, Susilo Prihranto at Diponegoro University (Internal Medicine Residency Program), and technicians at the laboratory of Microbiology and Infectious Diseases of Erasmus Medical Centre.
We declare that we have no conflicts of interest.
Footnotes
Published ahead of print 13 March 2013
REFERENCES
- 1. Liam CK, Pang YK, Poosparajah S. 2006. Pulmonary tuberculosis presenting as community-acquired pneumonia. Respirology 11:786–792 [DOI] [PubMed] [Google Scholar]
- 2. Cardozo DM, Nascimento-Carvalho CM, Andrade A-L, Silvany-Neto AM, Daltro CHC, Brandao M-A, Brandao AP, Brandileone M-CC. 2008. Prevalence and risk factors for nasopharyngeal carriage of Streptococcus pneumoniae among adolescents. J. Med. Microbiol. 57:185–189 [DOI] [PubMed] [Google Scholar]
- 3. Directorate General of Disease Control and Environmental Health, Ministry of Health, Republic of Indonesia 2007. Technical guidance for healthy house assessment, 2nd ed Ministry of Health, Jakarta, Republic of Indonesia: (In Indonesian.) [Google Scholar]
- 4. Parm Ü, Metsvaht T, Sepp E, Ilmoja M-L, Pisarev H, Pauskar M, Lutsar I. 2011. Risk factors associated with gut and nasopharyngeal colonization by common Gram-negative species and yeasts in neonatal intensive care units patients. Early Hum. Dev. 87:391–399 [DOI] [PubMed] [Google Scholar]
- 5. Lima ABM, Leão LSNDO, Oliveira LSDC, Pimenta FC. 2010. Nasopharyngeal Gram-negative bacilli colonization in Brazilian children attending day-care centers. Braz. J. Microbiol. 41:24–27 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6. Panda SK, Patra AK, Kar RN. 2012. Monitoring of multiple drug-resistant pathogens in a selected stretch of Bay of Bengal, India. Environ. Monit. Assess. 184:193–200 [DOI] [PubMed] [Google Scholar]
- 7. Haryani Y, Noorzaleha AS, Fatimah AB, Noorjahan BA, Patrick GB, Shamsinar AT, Laila RAS, Son R. 2007. Incidence of Klebsiella pneumonia in street foods sold in Malaysia and their characterization by antibiotic resistance, plasmid profiling, and RAPD–PCR analysis. Food Control 18:847–853 [Google Scholar]
- 8. Liu W, Zhang J, Hashim JH, Jalaludin J, Hashim Z, Goldstein BD. 2003. Mosquito coil emissions and health implications. Environ. Health Perspect. 111:1454–1460 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9. Lestari ES, Severin JA, Filius PMG, Kuntaman K, Duerink DO, Hadi U, Wahjono H, Verbrugh HA. 2008. Antimicrobial resistance among commensal isolates of Escherichia coli and Staphylococcus aureus in the Indonesian population inside and outside hospitals. Eur. J. Clin. Microbiol. Infect. Dis. 27:45–51 [DOI] [PubMed] [Google Scholar]
- 10. Severin JA, Lestari ES, Kloezen W, Lemmens-den Toom N, Mertaniasih NM, Kuntaman K, Purwanta M, Duerink DO, Hadi U, van Belkum A, Verbrugh HA, Goessens WH, Antimicrobial Resistance in Indonesia, Prevalence and Prevention (AMRIN) Study Group 2012. Faecal carriage of extended-spectrum β-lactamase-producing Enterobacteriaceae among humans in Java, Indonesia, in 2001–2002. Trop. Med. Int. Health 17:455–461 [DOI] [PubMed] [Google Scholar]