Thoracostomy Tube Infections: Prevalence and Associated Clinical Characteristics at a Tertiary Hospital in Northern Tanzania

A prospective cohort study at KCMC Zonal Referral Hospital in Northern Tanzania revealed a 26.2% prevalence of thoracostomy tube infections, primarily caused by *Pseudomonas aeruginosa* and *Staphylococcus aureus*, with prolonged tube duration and non-surgical ward admission identified as key risk factors.

The Gist

Imagine your body is a house, and sometimes, due to an injury or surgery, a storm (like fluid, blood, or air) gets trapped in the attic (your chest cavity). To fix this, doctors install a "drain pipe" called a thoracostomy tube to let the bad stuff out and let the house breathe again.

This study, conducted at a major hospital in Northern Tanzania, asked a simple but critical question: How often does this drain pipe itself get infected, and what causes it?

Here is the story of their findings, broken down into everyday concepts.

1. The Problem: The Drain Pipe Gets Clogged with Germs

The researchers looked at 84 patients who had these drain pipes installed. Unfortunately, 26 out of 100 (about 26%) developed an infection at the site where the tube entered their skin.

Think of it like leaving a garden hose connected to your house for too long. Eventually, the connection point gets dirty, and bacteria start to grow. In this study, the "garden hose" (the chest tube) became a breeding ground for germs in over a quarter of the patients.

2. The Villains: Who is Invading?

When they tested the infections, they found the "bad guys" (bacteria) hiding there.

• The Top Criminals: The most common invaders were Pseudomonas aeruginosa (about 41%) and Staphylococcus aureus (about 29%).
• The Resistance: These bacteria were tough. They were like ninjas wearing armor that made many standard antibiotics useless.
  • The "Magic Bullet": The only antibiotic that worked well against most of these germs was Amikacin.
  • The "Useless Weapons": Many common antibiotics (like Ceftazidime and Piperacillin-Tazobactam) failed to stop the bacteria more than half the time. This is a warning sign that the bacteria are becoming "superbugs" that are hard to kill.

3. The Culprits: What Made the Infection Worse?

The study looked for clues on why some people got infected and others didn't. They found two main "smoking guns":

• Leaving the Pipe In Too Long: This was the biggest factor. If the tube stayed in for more than 7 days, the risk of infection skyrocketed.
  • Analogy: Imagine wearing a cast on your arm. If you wear it for a week, it's fine. If you wear it for a month without cleaning it properly, it gets smelly and infected. The longer the tube stays in, the more time bacteria have to build a "fortress" (called a biofilm) around it.
• The Wrong Neighborhood: Patients who were moved to non-surgical wards (general medical wards) got infected much more often than those who stayed in the surgical ward.
  • Analogy: Think of the surgical ward as a "sterile kitchen" where the staff are experts at handling dirty dishes and keeping things clean. The non-surgical ward is like a "general living room." While the living room is nice, the staff there might not be as specialized in caring for a delicate drain pipe, leading to more accidents and infections.

4. The Takeaway: What Should We Do?

The study concludes with a clear message for doctors and patients:

1. Don't wait too long: If the drain pipe isn't needed anymore, pull it out! The longer it stays, the higher the chance of infection.
2. Specialized care matters: Patients with chest tubes need to be looked after by teams who know exactly how to care for them (like the surgical team), rather than just general care.
3. Pick the right medicine: Since the bacteria are resistant to many common drugs, doctors need to test the germs first to know which "weapon" (antibiotic) will actually work.

In a nutshell:
Chest tubes are life-saving tools, but they are like open windows during a storm. If you leave the window open too long, or if you don't have the right security guard (specialized care) watching it, the bad guys (bacteria) will sneak in. The solution is to close the window (remove the tube) as soon as the storm passes and make sure the right people are guarding the house.

Technical Summary

1. Problem Statement

Thoracostomy tube insertion is a critical procedure for draining fluid, blood, or air from the pleural cavity, indicated for conditions such as pneumothorax, empyema, and haemothorax. However, it carries a significant risk of infectious complications, including surgical site infections (SSI), empyema, and necrotizing fasciitis.

• Global Context: Infection rates for thoracostomy tubes range from 2% to 25% globally.
• Local Gap: In Northern Tanzania, there is a lack of localized data regarding the specific microbial profiles, antimicrobial resistance (AMR) patterns, and risk factors associated with these infections.
• Clinical Challenge: The absence of local guidelines forces clinicians to rely on empirical broad-spectrum antibiotics, which contributes to rising AMR and suboptimal patient outcomes. The debate regarding the routine use of prophylactic antibiotics remains unresolved due to insufficient evidence.

2. Methodology

• Study Design: A hospital-based prospective cohort study.
• Setting: Kilimanjaro Christian Medical Centre (KCMC), a 734-bed tertiary referral hospital in Moshi, Northern Tanzania.
• Study Period: September 2024 to April 2025.
• Population: 84 patients who underwent tube thoracostomy insertion.
• Sampling: Convenience sampling was used. All consenting patients meeting inclusion criteria were enrolled.
• Data Collection:
  • Clinical Data: Demographics, comorbidities, indication for insertion (trauma vs. non-trauma), urgency (emergency vs. elective), duration of tube stay, and ward of admission.
  • Microbiological Data: Pus swabs from wound sites and pleural fluid aspirates were collected from patients showing signs of infection. Samples were cultured, and isolates underwent antimicrobial susceptibility testing.
• Statistical Analysis: Data were analyzed using SPSS version 23. Descriptive statistics were used for demographics. Chi-square tests identified associations, and multivariable logistic regression determined independent predictors of infection (significance level $p < 0.05$).

3. Key Contributions

This study provides the first comprehensive, localized epidemiological data on thoracostomy tube infections in Northern Tanzania. Its primary contributions include:

1. Establishing Local Prevalence: Quantifying the infection rate in a resource-limited tertiary setting.
2. Microbial Profiling: Identifying the specific bacterial pathogens responsible for these infections in the region.
3. Resistance Patterns: Mapping the antimicrobial susceptibility and resistance profiles of isolated organisms to guide empirical therapy.
4. Risk Factor Identification: Statistically validating clinical and environmental factors (e.g., tube duration, ward type) that predict infection.

4. Key Results

A. Prevalence and Demographics

• Total Cohort: 84 patients.
• Infection Rate: 22 patients (26.2%) developed a Surgical Site Infection (SSI).
• Culture Positivity: Of the 22 SSI cases, 17 (77.3%) yielded positive culture results; 5 were culture-negative.
• Demographics: Median age was 41.5 years; 56% were male. Most insertions (77.4%) were performed in emergency settings.

B. Microbial Profile

Among the 17 positive isolates, the dominant pathogens were:

• Pseudomonas aeruginosa: 41.2% (7 isolates).
• Staphylococcus aureus: 29.4% (5 isolates).
• Other Isolates: Acinetobacter baumannii (3), Citrobacter freundii (1), and Klebsiella pneumoniae (1).
• Context: Most isolates were recovered from patients in non-surgical wards and those with non-traumatic indications.

C. Antimicrobial Susceptibility and Resistance

• Most Effective Antibiotic: Amikacin showed the highest susceptibility, effective against 58.8% (10/17) of isolates.
• High Resistance Rates:
  • Ceftazidime: 56.3% resistance.
  • Piperacillin-Tazobactam: 50.0% resistance.
  • Ciprofloxacin: 43.8% resistance.
  • A. baumannii: Demonstrated 100% resistance to Ceftriaxone, Meropenem, Trimethoprim-Sulfamethoxazole, Piperacillin-Tazobactam, and Cefazolin.
  • C. freundii: 100% resistance to Ceftriaxone, Piperacillin-Tazobactam, and Ampicillin.
• S. aureus: Showed lower overall resistance, with the highest resistance to Erythromycin (30%).

D. Risk Factors for Infection

• Univariate Analysis: Significant associations were found between SSI and:
  • Duration of Tube Stay: >7 days ($p < 0.001$).
  • Ward of Admission: Non-surgical wards ($p = 0.003$).
  • Indication: Non-traumatic causes ($p = 0.006$).
  • Comorbidities: Presence of comorbidities ($p = 0.001$).
• Multivariable Logistic Regression:
  • Prolonged Tube Duration (>7 days) was identified as the strongest independent predictor of SSI (Adjusted Odds Ratio [aOR] = 1.39; 95% CI: 1.18–1.64; $p < 0.001$).
  • While admission to non-surgical wards and non-traumatic indications were significant in univariate analysis, they did not remain independent predictors in the final multivariable model, though they remain clinically relevant.

5. Significance and Implications

• Clinical Practice: The study highlights that prolonged chest tube duration is the most critical modifiable risk factor. Clinicians are urged to remove tubes as soon as clinically feasible to reduce infection risk.
• Infection Control: The higher infection rate in non-surgical wards suggests that specialized surgical care (including hygiene protocols and dressing changes) is crucial. Improving care standards in general medical wards is recommended.
• Antibiotic Stewardship: Given the high resistance to Ceftriaxone (a common first-line drug) and Piperacillin-Tazobactam, empirical treatment for thoracostomy infections in this region should be reconsidered. Amikacin and Ciprofloxacin showed better susceptibility profiles, though local resistance patterns must be monitored closely.
• Policy: The findings support the need for local guidelines on empirical antibiotic selection and the routine monitoring of chest tube duration to mitigate the burden of multidrug-resistant organisms.

Conclusion: The study reveals a high prevalence (26.2%) of thoracostomy tube infections in Northern Tanzania, driven primarily by prolonged tube duration and managed by specific microbial profiles with significant multidrug resistance. Immediate removal of tubes and optimized ward care are essential strategies to mitigate these risks.