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Pneumococcal infections in Victoria, Australia
Vaccine 17 (1999) S119±S121
ww.elsevier.com/locate/vaccine
Pneumococcal infections in Victoria, Australia Georey Hogg, Janet Strachan Microbiological Diagnostic Unit, Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
1. Causes of morbidity and mortality The state of Victoria, with 4.5 million people, comprises one-quarter of the Australian population. Health statistics from the Australian Bureau of Statistics indicate that Victoria is representative of the Australian population as a whole. Data from the 1995±1996 National Health Survey [1] indicate that respiratory illness are the major cause of morbidity in the Victoria population. 363/1000 persons reported suering a recent or long-term respiratory condition, mainly hayfever, asthma and sinusitis. Cardiovascular disease, the second most commonly reported cause of morbidity, was also the greatest cause of mortality, contributing to 400/1000 deaths [2] in 1996. Diabetes mellitus was a major cause of both morbidity (24/ 1000) and mortality (30/1000). 2. Pneumonia incidence by age Incidence rates of pneumonia by age group within Victoria are available only for those patients who have been hospitalized. The ®gures in Table 1 refer to patients with hospital discharge diagnoses ICD9 codes of 481 (pneumococcal pneumonia), 485 (bronchopneumonia, organism not elsewhere classi®ed) and 486 (pneumonia, organism not otherwise speci®ed). The data were obtained from the Victorian Minimum Inpatient Database for 1992. 3. Mortality rates among patients hospitalized with pneumonia No ®gures are currently available on the mortality rates of patients hospitalized with pneumonia. The data given in Table 2 correspond to the single underlying cause of death as reported on death certi®cates.
The mortality rate due to the pneumonia or in¯uenza remains low until the age of 65.
4. Impact of Pneumococcus No recent data are available on the proportion of hospitalized cases of pneumonia in Victoria in which a pathogen has been identi®ed, although hospital discharge ICD9 diagnosis codes, as reported from the Victorian Inpatient Minimum Database in 1992, indicate that pneumococcal pneumonia represents 32% of all diagnoses of pneumonia (ICD9 codes 481, 485 and 486). The Victoria Hospital Pathogens Surveillance Scheme (VHPSS) receives noti®cation of bloodstream and cerebrospinal ¯uid infections from throughout the state of Victoria. Review of the records of 479 infections reported to the VHPSS in 1994±1995 indicates an overall incidence of 6.1 cases per 100,000 of pneumococcal pneumonia with bacteraemia. This ®gure increases to 28.1 for people over 65 years of age; 4.7% of these bacteraemic pneumonias were nosocomially acquired. The mortality rate for bacteraemic pneumonia was 15%, rising to 24% for people r65 years old.
5. Pneumococcal serotypes Pneumococcal serotyping has been performed at the Microbiological Diagnostic Unit at the University of Melbourne since 1994. Isolates are sent from most laboratories throughout the state of Victoria in conjunction with noti®cation to the VHPSS of bloodstream or cerebrospinal ¯uid infection. The vaccine coverage rate based on 779 invasive isolates received in 1994±1996, is 95.5%. The serotypes isolated in 1994±1996 are shown in Table 3.
0264-410X/99/$ - see front matter # 1999 Published by Elsevier Science Ltd. All rights reserved. PII: S 0 2 6 4 - 4 1 0 X ( 9 9 ) 0 0 1 2 0 - 6
S120
G. Hogg, J. Strachan / Vaccine 17 (1999) S119±S121
Table 1 Pneumonia hospitalization by age, Victoria, Australia, 1992 Age group (years) No. of cases hospitalized Incidence (per 100,000) <1 1±4 5±9 10±14 15±19 20±24 25±29 30±34 35±39 40±44 45±49 50±54 55±59 60±64 65±69 70±74 75±79 >80
185 462 264 129 90 122 139 149 158 159 172 223 297 423 617 776 927 1697
308 178 85 42 29 34 40 41 45 49 55 93 146 236 348 514 909 1397
Total
6989
155
6. Antibiotic resistance In 1997, 102 consecutive invasive pneumococcal isolates received at the Microbiological Diagnostic Unit
Table 2 Pneumonia or in¯uenza as cause of death, Victoria, Australia, 1993 [3] Age group (years)
No. of deaths
Incidence (per 100,000)
<1 1±14 15±24 25±44 45±54 55±64 65±74 75±84 >85
2 1 0 13 9 16 56 107 244
3 0.1 0 0.9 2 4 17 62 558
Total
448
10
for serotyping were also tested for susceptibility to a range of antimicrobials. The percentages of strains that were found to be intermediate or resistant were: penicillin (11.8%), erythromycin (7.8%), ceftriaxone (3.9%), tetracycline (1.0%) and cotrimoxazole (26.5%). Resistance to three or more of these antibiotics was found in 4.9% of isolates. The penicillin-intermediate or -resistant strains all belonged to serotypes 9V, 19F, 23F or 6B. The level of antimicrobial resistance appears to be increasing. An Australia-wide study performed in 1995
Table 3 Pneumococcal serotypes of invasive isolates of pneumococcus, Victoria, Australia, 1994±1996 Strains included in vaccine
No. of isolates
1 2 3 4 5 6B (6A) 7F 8 9N 9V 10A 11A 12F 14 15B 17F 18C 19A 19F 20 22F 23F 33F Non vaccine strains (11F, 12A, 13, 15C, 16, 17B, 18B, 18F, 31, 35, 38, 40, not typable)
14 0 35 77 0 69 (17) 13 6 22 51 3 9 1 209 6 4 36 71 11 6 21 57 6 35
Total
779
% 1.8 0 4.5 9.9 0 8.9 (2.2) 1.7 0.8 2.8 6.5 0.4 1.2 0.1 26.8 0.8 0.5 4.6 9.1 1.4 0.8 2.7 7.3 0.8 4.5 100
G. Hogg, J. Strachan / Vaccine 17 (1999) S119±S121
[4] found that 3.5% of invasive strains had diminished susceptibility to penicillin, whereas 11.8% were detected in Victoria in 1997.
References [1] Australian Bureau of Statistics 1997 National Health Survey.
S121
Summary results: Australian States and Territories. ABS catalogue ]]4368.0. [2] Australian Bureau of Statistics. Causes of Death. Victoria 1996. ABS Catalogue ]]3303.0. [3] Australian Bureau of Statistics. Causes of Death Australia 1993. ABS Catalogue ]]3312.2. [4] Collignon PJ, Bell JM, the Australian Group on Antimicrobial Resistance (AGAR). Drug-resistant Streptococcus pneumoniae: the beginning of the end for many antibiotics? MJA 1996;164:64±7.
ww.elsevier.com/locate/vaccine
Pneumococcal infections in Victoria, Australia Georey Hogg, Janet Strachan Microbiological Diagnostic Unit, Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
1. Causes of morbidity and mortality The state of Victoria, with 4.5 million people, comprises one-quarter of the Australian population. Health statistics from the Australian Bureau of Statistics indicate that Victoria is representative of the Australian population as a whole. Data from the 1995±1996 National Health Survey [1] indicate that respiratory illness are the major cause of morbidity in the Victoria population. 363/1000 persons reported suering a recent or long-term respiratory condition, mainly hayfever, asthma and sinusitis. Cardiovascular disease, the second most commonly reported cause of morbidity, was also the greatest cause of mortality, contributing to 400/1000 deaths [2] in 1996. Diabetes mellitus was a major cause of both morbidity (24/ 1000) and mortality (30/1000). 2. Pneumonia incidence by age Incidence rates of pneumonia by age group within Victoria are available only for those patients who have been hospitalized. The ®gures in Table 1 refer to patients with hospital discharge diagnoses ICD9 codes of 481 (pneumococcal pneumonia), 485 (bronchopneumonia, organism not elsewhere classi®ed) and 486 (pneumonia, organism not otherwise speci®ed). The data were obtained from the Victorian Minimum Inpatient Database for 1992. 3. Mortality rates among patients hospitalized with pneumonia No ®gures are currently available on the mortality rates of patients hospitalized with pneumonia. The data given in Table 2 correspond to the single underlying cause of death as reported on death certi®cates.
The mortality rate due to the pneumonia or in¯uenza remains low until the age of 65.
4. Impact of Pneumococcus No recent data are available on the proportion of hospitalized cases of pneumonia in Victoria in which a pathogen has been identi®ed, although hospital discharge ICD9 diagnosis codes, as reported from the Victorian Inpatient Minimum Database in 1992, indicate that pneumococcal pneumonia represents 32% of all diagnoses of pneumonia (ICD9 codes 481, 485 and 486). The Victoria Hospital Pathogens Surveillance Scheme (VHPSS) receives noti®cation of bloodstream and cerebrospinal ¯uid infections from throughout the state of Victoria. Review of the records of 479 infections reported to the VHPSS in 1994±1995 indicates an overall incidence of 6.1 cases per 100,000 of pneumococcal pneumonia with bacteraemia. This ®gure increases to 28.1 for people over 65 years of age; 4.7% of these bacteraemic pneumonias were nosocomially acquired. The mortality rate for bacteraemic pneumonia was 15%, rising to 24% for people r65 years old.
5. Pneumococcal serotypes Pneumococcal serotyping has been performed at the Microbiological Diagnostic Unit at the University of Melbourne since 1994. Isolates are sent from most laboratories throughout the state of Victoria in conjunction with noti®cation to the VHPSS of bloodstream or cerebrospinal ¯uid infection. The vaccine coverage rate based on 779 invasive isolates received in 1994±1996, is 95.5%. The serotypes isolated in 1994±1996 are shown in Table 3.
0264-410X/99/$ - see front matter # 1999 Published by Elsevier Science Ltd. All rights reserved. PII: S 0 2 6 4 - 4 1 0 X ( 9 9 ) 0 0 1 2 0 - 6
S120
G. Hogg, J. Strachan / Vaccine 17 (1999) S119±S121
Table 1 Pneumonia hospitalization by age, Victoria, Australia, 1992 Age group (years) No. of cases hospitalized Incidence (per 100,000) <1 1±4 5±9 10±14 15±19 20±24 25±29 30±34 35±39 40±44 45±49 50±54 55±59 60±64 65±69 70±74 75±79 >80
185 462 264 129 90 122 139 149 158 159 172 223 297 423 617 776 927 1697
308 178 85 42 29 34 40 41 45 49 55 93 146 236 348 514 909 1397
Total
6989
155
6. Antibiotic resistance In 1997, 102 consecutive invasive pneumococcal isolates received at the Microbiological Diagnostic Unit
Table 2 Pneumonia or in¯uenza as cause of death, Victoria, Australia, 1993 [3] Age group (years)
No. of deaths
Incidence (per 100,000)
<1 1±14 15±24 25±44 45±54 55±64 65±74 75±84 >85
2 1 0 13 9 16 56 107 244
3 0.1 0 0.9 2 4 17 62 558
Total
448
10
for serotyping were also tested for susceptibility to a range of antimicrobials. The percentages of strains that were found to be intermediate or resistant were: penicillin (11.8%), erythromycin (7.8%), ceftriaxone (3.9%), tetracycline (1.0%) and cotrimoxazole (26.5%). Resistance to three or more of these antibiotics was found in 4.9% of isolates. The penicillin-intermediate or -resistant strains all belonged to serotypes 9V, 19F, 23F or 6B. The level of antimicrobial resistance appears to be increasing. An Australia-wide study performed in 1995
Table 3 Pneumococcal serotypes of invasive isolates of pneumococcus, Victoria, Australia, 1994±1996 Strains included in vaccine
No. of isolates
1 2 3 4 5 6B (6A) 7F 8 9N 9V 10A 11A 12F 14 15B 17F 18C 19A 19F 20 22F 23F 33F Non vaccine strains (11F, 12A, 13, 15C, 16, 17B, 18B, 18F, 31, 35, 38, 40, not typable)
14 0 35 77 0 69 (17) 13 6 22 51 3 9 1 209 6 4 36 71 11 6 21 57 6 35
Total
779
% 1.8 0 4.5 9.9 0 8.9 (2.2) 1.7 0.8 2.8 6.5 0.4 1.2 0.1 26.8 0.8 0.5 4.6 9.1 1.4 0.8 2.7 7.3 0.8 4.5 100
G. Hogg, J. Strachan / Vaccine 17 (1999) S119±S121
[4] found that 3.5% of invasive strains had diminished susceptibility to penicillin, whereas 11.8% were detected in Victoria in 1997.
References [1] Australian Bureau of Statistics 1997 National Health Survey.
S121
Summary results: Australian States and Territories. ABS catalogue ]]4368.0. [2] Australian Bureau of Statistics. Causes of Death. Victoria 1996. ABS Catalogue ]]3303.0. [3] Australian Bureau of Statistics. Causes of Death Australia 1993. ABS Catalogue ]]3312.2. [4] Collignon PJ, Bell JM, the Australian Group on Antimicrobial Resistance (AGAR). Drug-resistant Streptococcus pneumoniae: the beginning of the end for many antibiotics? MJA 1996;164:64±7.