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EID Journal: Chlamydia pneumoniae Upsurge at a Tertiary Hospital, Lausanne, Switzerland
Credit EID Journal
#17,936
Over the past year we've seen numerous outbreaks of CAP (Community Acquired Pneumonia) around the world, with large epidemics of Mycoplasma Pneumonia reported last fall in China (see WHO Statement (DON) On Respiratory Illness Surge Reported In Northern China), along with outbreaks in Europe (see ECDC On Increased Mycoplasma Pneumonia Reported In EU/EEA Countries).
Late last week we looked at a report from Denmark's SSI on a Marked Increase In Parrot Fever Cases Over the Past 60 Days, and we've seen a recent risk assessment on increased incidence of Hypervirulent Carbapenem-Resistant Klebsiella pneumoniae in the EU/EEA as well.
Often the cause of CAP goes undetermined. A 2015 study published in the NEJM (see The CDC’s EPIC CA-Pneumonia Study) followed 2500 cases over 5 years and found that in the majority (62%) of cases no definitive pathogenic agent was identified.
Today we've a research letter, published last week in the CDC's EID Journal, on another recent surge in CAP - this time Chlamydia pneumoniae (not to be confused with Chlamydia psittaci aka `Parrot Fever') - in Switzerland.
While C. pneumoniae infection often produces only mild disease, serious complications can occur, including encephalitis and myocarditis. According to the CDC this bacterial infection is increasingly resistant to penicillin, Ampicillin, and Sulfa drugs it is still generally susceptible to Macrolides, Tetracyclines and Fluoroquionolones.
First some excerpts, then I'll return with a bit more.
Abstract
Chlamydia pneumoniae infection cases have usually accounted for <1.5% of community-acquired respiratory tract infections. Currently, Lausanne, Switzerland is experiencing a notable upsurge in cases, with 28 reported within a span of a few months. This upsurge in cases highlights the need for heightened awareness among clinicians.
The intracellular bacterium Chlamydia pneumoniae is a recognized cause of community-acquired pneumonia (1). High-frequency estimates were initially derived from serologic studies, but the advent of molecular techniques has revealed rates that are generally <1.5% among patients with respiratory tract infections, although epidemiological change between initial and current rate estimates cannot be ruled out (2,3). Sporadic outbreaks have been documented, such as a 2014 prison outbreak in Texas (4) and a 2016 community-acquired pneumonia outbreak in South Korea (5). In recent years, studies have also linked C. pneumoniae bacteria to bronchitis and asthma (6). C. pneumoniae bacteria has also been documented in patients with cystic fibrosis (7). Of note, infections occur at higher rates in children than in adults (2).
At the height of the SARS-CoV-2 pandemic, C. pneumoniae bacteria detection rates were low, paralleling the near-extinction state observed for Mycoplasma pneumoniae bacteria in Europe (8). However, a current rebound of M. pneumoniae infections is occurring (9). We report a similar increase in PCR-positive C. pneumoniae bacteria detection rates at a tertiary hospital in Switzerland. As the case series and the analysis thereof derive from the pathogen surveillance to which our institute is legally bound by the health authorities, Swiss legislation on human research is not applicable and the consent of the patients concerned is not required. This publication complies with the applicable data protection legislation and institutional guidelines.
During routine epidemiologic surveillance at Lausanne University Hospital in Lausanne, Switzerland, positive C. pneumoniae bacteria PCR rates surged to 3.61% during October–December 2023, peaking at 6.66% in October, contrasting with the usual 0%–0.75% range reported over the past decade (Figure 1, panel A, B). The PCR method we used for testing has been previously described in Opota et al. (10).
In this most recent outbreak, we documented C. pneumoniae bacteria in 28 patients in 2023; of those, 20 were children (mean age 8 years) and 8 were adults (mean age 43 years). Patients with C. pneumoniae bacteria sometimes reported wheezing as a major clinical complaint. We tested bacterial loads in patients positive for C. pneumoniae bacteria and found that the mean bacterial load was 1,534,821 DNA copies/mL (range 200–11,998,897 DNA copies/mL). We collected nasopharyngeal swabs most frequently (n = 24), whereas we collected sputum samples (n = 5) and nasal swab samples (nostril only, n = 1) less frequently. Of note, bacterial loads were not higher in the analyzed sputa than in the nasopharyngeal swabs (p = 1 by Wilcoxon rank-sum test) (Figure 2).
The results of this analysis should be interpreted with caution in the absence of a larger number of paired samples. This analysis includes only 2 paired samples exhibiting <1 logarithm (decimal) of difference in DNA copies per milliliter.
To explain this sudden surge of C. pneumoniae bacterial infection, we suspect 2 primary factors. First, decreased immunity may have developed because of fewer circulating strains in the population over the past 3 years, related to SARS-CoV-2 transmission prevention measures. Second, recently relaxed hygiene standards after the SARS-CoV-2 pandemic may have increased the risk for infection.
(SNIP)
In conclusion, we outline an upsurge of C. pneumoniae bacterial infections in the Lausanne region of Switzerland, especially in the pediatric population, raising concerns for other settings and regions. We found no clear epidemiologic link between patients, which suggests that we are detecting a minority of cases and that infections may occur at higher rates in the community than we have documented. This local finding highlights the importance of considering this intracellular bacterium as a causative agent, along with other fastidious organisms such as M. pneumoniae bacteria, which are also on the rise (9).
Dr. Tagini is a trainee in clinical microbiology and infectious diseases at the Lausanne University Hospital. His research interests are focused mainly on intracellular bacteria and bacterial genomics.
As we discussed last December in China's Growing Antibiotic Resistance Problem, overuse of antibiotics has led to greatly increased AMR (antimicrobial resistance) among common CAP bacteria in Asia.
Resistance runs as high as 90% in parts of China - with rates in the United States estimated at roughly 10%, and even lower in much of Europe (see chart below).
We live in a hugely interconnect world, and the odds that these resistant pathogens will remain sequestered in Asia are remote.
As we've discussed often (see here, here, and here), every year we draw a little closer to an oft-predicted `post-antibiotic era', where something as simple as a scraped knee, community acquired pneumonia (CAP), or elective surgery, could prove deadly.
Antibiotics still work today for most infections, but for tens of thousands of people every year, the `post-antibiotic era' is already here. According to a recent report from the CDC:
In the 2019 report, the last year comprehensive healthcare and community data were available to calculate, CDC estimated that more than 2.8 million antimicrobial-resistant infections occur in the U.S. each year, with more than 35,000 people dying as a result.
Complicating matters, the prolonged COVID pandemic proved to be a setback for the fight against antimicrobial resistance in the United States (see below), and presumably many other places in the world.
Short of seeing another COVID or 1918-like pandemic, the biggest threat to global health over the next decade or two is undoubtedly antimicrobial resistance.
While I cover AMR topics occasionally in this blog, I can heartily recommend CIDRAP's Antimicrobial Stewardship Project as the best place to learn about the growing global threat of AMR.
Credit EID Journal
#17,936
Over the past year we've seen numerous outbreaks of CAP (Community Acquired Pneumonia) around the world, with large epidemics of Mycoplasma Pneumonia reported last fall in China (see WHO Statement (DON) On Respiratory Illness Surge Reported In Northern China), along with outbreaks in Europe (see ECDC On Increased Mycoplasma Pneumonia Reported In EU/EEA Countries).
Late last week we looked at a report from Denmark's SSI on a Marked Increase In Parrot Fever Cases Over the Past 60 Days, and we've seen a recent risk assessment on increased incidence of Hypervirulent Carbapenem-Resistant Klebsiella pneumoniae in the EU/EEA as well.
Often the cause of CAP goes undetermined. A 2015 study published in the NEJM (see The CDC’s EPIC CA-Pneumonia Study) followed 2500 cases over 5 years and found that in the majority (62%) of cases no definitive pathogenic agent was identified.
Today we've a research letter, published last week in the CDC's EID Journal, on another recent surge in CAP - this time Chlamydia pneumoniae (not to be confused with Chlamydia psittaci aka `Parrot Fever') - in Switzerland.
While C. pneumoniae infection often produces only mild disease, serious complications can occur, including encephalitis and myocarditis. According to the CDC this bacterial infection is increasingly resistant to penicillin, Ampicillin, and Sulfa drugs it is still generally susceptible to Macrolides, Tetracyclines and Fluoroquionolones.
First some excerpts, then I'll return with a bit more.
Florian Tagini, Onya Opota, and Gilbert Greub
Author affiliation: Institute of Microbiology, Lausanne University Hospital, Lausanne, Switzerland
Author affiliation: Institute of Microbiology, Lausanne University Hospital, Lausanne, Switzerland
Abstract
Chlamydia pneumoniae infection cases have usually accounted for <1.5% of community-acquired respiratory tract infections. Currently, Lausanne, Switzerland is experiencing a notable upsurge in cases, with 28 reported within a span of a few months. This upsurge in cases highlights the need for heightened awareness among clinicians.
The intracellular bacterium Chlamydia pneumoniae is a recognized cause of community-acquired pneumonia (1). High-frequency estimates were initially derived from serologic studies, but the advent of molecular techniques has revealed rates that are generally <1.5% among patients with respiratory tract infections, although epidemiological change between initial and current rate estimates cannot be ruled out (2,3). Sporadic outbreaks have been documented, such as a 2014 prison outbreak in Texas (4) and a 2016 community-acquired pneumonia outbreak in South Korea (5). In recent years, studies have also linked C. pneumoniae bacteria to bronchitis and asthma (6). C. pneumoniae bacteria has also been documented in patients with cystic fibrosis (7). Of note, infections occur at higher rates in children than in adults (2).
At the height of the SARS-CoV-2 pandemic, C. pneumoniae bacteria detection rates were low, paralleling the near-extinction state observed for Mycoplasma pneumoniae bacteria in Europe (8). However, a current rebound of M. pneumoniae infections is occurring (9). We report a similar increase in PCR-positive C. pneumoniae bacteria detection rates at a tertiary hospital in Switzerland. As the case series and the analysis thereof derive from the pathogen surveillance to which our institute is legally bound by the health authorities, Swiss legislation on human research is not applicable and the consent of the patients concerned is not required. This publication complies with the applicable data protection legislation and institutional guidelines.
During routine epidemiologic surveillance at Lausanne University Hospital in Lausanne, Switzerland, positive C. pneumoniae bacteria PCR rates surged to 3.61% during October–December 2023, peaking at 6.66% in October, contrasting with the usual 0%–0.75% range reported over the past decade (Figure 1, panel A, B). The PCR method we used for testing has been previously described in Opota et al. (10).
In this most recent outbreak, we documented C. pneumoniae bacteria in 28 patients in 2023; of those, 20 were children (mean age 8 years) and 8 were adults (mean age 43 years). Patients with C. pneumoniae bacteria sometimes reported wheezing as a major clinical complaint. We tested bacterial loads in patients positive for C. pneumoniae bacteria and found that the mean bacterial load was 1,534,821 DNA copies/mL (range 200–11,998,897 DNA copies/mL). We collected nasopharyngeal swabs most frequently (n = 24), whereas we collected sputum samples (n = 5) and nasal swab samples (nostril only, n = 1) less frequently. Of note, bacterial loads were not higher in the analyzed sputa than in the nasopharyngeal swabs (p = 1 by Wilcoxon rank-sum test) (Figure 2).
The results of this analysis should be interpreted with caution in the absence of a larger number of paired samples. This analysis includes only 2 paired samples exhibiting <1 logarithm (decimal) of difference in DNA copies per milliliter.
To explain this sudden surge of C. pneumoniae bacterial infection, we suspect 2 primary factors. First, decreased immunity may have developed because of fewer circulating strains in the population over the past 3 years, related to SARS-CoV-2 transmission prevention measures. Second, recently relaxed hygiene standards after the SARS-CoV-2 pandemic may have increased the risk for infection.
(SNIP)
In conclusion, we outline an upsurge of C. pneumoniae bacterial infections in the Lausanne region of Switzerland, especially in the pediatric population, raising concerns for other settings and regions. We found no clear epidemiologic link between patients, which suggests that we are detecting a minority of cases and that infections may occur at higher rates in the community than we have documented. This local finding highlights the importance of considering this intracellular bacterium as a causative agent, along with other fastidious organisms such as M. pneumoniae bacteria, which are also on the rise (9).
Dr. Tagini is a trainee in clinical microbiology and infectious diseases at the Lausanne University Hospital. His research interests are focused mainly on intracellular bacteria and bacterial genomics.
As we discussed last December in China's Growing Antibiotic Resistance Problem, overuse of antibiotics has led to greatly increased AMR (antimicrobial resistance) among common CAP bacteria in Asia.
Resistance runs as high as 90% in parts of China - with rates in the United States estimated at roughly 10%, and even lower in much of Europe (see chart below).
Credit: The molecular characteristics, diagnosis, and treatment of macrolide-resistant Mycoplasma pneumoniae in children Frontiers in Peds. March 2023
We live in a hugely interconnect world, and the odds that these resistant pathogens will remain sequestered in Asia are remote.
As we've discussed often (see here, here, and here), every year we draw a little closer to an oft-predicted `post-antibiotic era', where something as simple as a scraped knee, community acquired pneumonia (CAP), or elective surgery, could prove deadly.
Antibiotics still work today for most infections, but for tens of thousands of people every year, the `post-antibiotic era' is already here. According to a recent report from the CDC:
In the 2019 report, the last year comprehensive healthcare and community data were available to calculate, CDC estimated that more than 2.8 million antimicrobial-resistant infections occur in the U.S. each year, with more than 35,000 people dying as a result.
Complicating matters, the prolonged COVID pandemic proved to be a setback for the fight against antimicrobial resistance in the United States (see below), and presumably many other places in the world.
Short of seeing another COVID or 1918-like pandemic, the biggest threat to global health over the next decade or two is undoubtedly antimicrobial resistance.
While I cover AMR topics occasionally in this blog, I can heartily recommend CIDRAP's Antimicrobial Stewardship Project as the best place to learn about the growing global threat of AMR.
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