Klebsiella pneumoniae Lung Abscess Due to Aspiration of Seawater During Recreational Free Diving

Abstract

Cough persisting for 5 wk, low-grade fever, and thick, pinkish to reddish, foul-tasting sputum made the doctors seeing this patient think of tuberculosis at first. However, a history of aspirating seawater during recreational free diving gave a clearer picture of how this patient got sick. Investigations later revealed a cavitary lesion in the right lung, and sputum culture grew Klebsiella pneumoniae, resulting in a diagnosis of lung abscess. This case is being reported to show this peculiar way that a bacterial pathogen entered the respiratory tree and that recreational free diving poses a health risk if done in a marine environment where this “survivor bacteria” thrives.

Dr Carisa Mariella Paraz: An otherwise healthy 44-y-old male living on Luzon Island, Philippines, presented to our clinic complaining of cough with phlegm that “tasted like fish guts.” Five weeks prior to his presentation, he reported experiencing malaise, nasal congestion, and sore throat. A week later, he developed a fever reaching 38.4°C, with night sweats, chills, joint pain, and tenderness of the submandibular lymph nodes. The patient self-medicated with paracetamol, chlorphenamine, ibuprofen, acetylcysteine/carbocisteine, and lagundi (Vitex negundo L leaf extract), which afforded relief during the day, but symptoms would worsen at night. Two weeks into the course of his illness, the patient reported that his sputum seemed thicker, was tinged with a pink to reddish color, and “tasted like fish guts.” The productive cough lasted ∼2 wk. At this point, the patient completed a 3-d prescription for azithromycin 500 mg. Although he reported rapid improvement in symptoms and decreased sputum production with azithromycin, he had a recurrence of productive cough with a fishy taste that prompted the current presentation to our clinic.

Dr Mark Anthony Sandoval: Does the patient have any pertinent medical history?

Dr Carisa Mariella Paraz: He reported a history of childhood asthma and 3-pack-year cigarette use (which had shifted to vape/e-cigarette use since 2010). Between 2010 and 2020, the patient consumed 6 mL·d^–1 of 3 g of nicotine e-juice. From 2021 to 2022, he reduced his e-cigarette use to 1 mL·d^–1 of 3 g nicotine e-juice because he also consumed heat-not-burn tobacco, 10 sticks per day.

Dr Mark Anthony Sandoval: How did he appear on presentation?

Dr Carisa Mariella Paraz: The patient was afebrile, with a heart rate of 72 beats/min, respiratory rate was 16 breaths/min, blood pressure was 110/70 mm Hg, and oxygen saturation was 97% to 99%. He was not in respiratory distress. Chest examination did not reveal crackles or any other abnormal sounds. The rest of the examination was normal. He was not able to expectorate sputum at the time of consultation.

Dr Mark Anthony Sandoval: Based on the clinical information, what is your primary working impression and differential diagnosis?

Dr Carisa Mariella Paraz: The main consideration for cough now lasting for 5 wk with constitutional symptoms and with pinkish to reddish sputum in the Philippines is pulmonary tuberculosis. Undertreated community-acquired pneumonia is also a consideration.

Dr Mark Anthony Sandoval: Did the patient have any exposure to tuberculosis? Is there any reason to suspect an immunocompromised state?

Dr Carisa Mariella Paraz: The patient did not have any exposure to a person known to have active tuberculosis. However, it should be emphasized that the Philippines has a heavy burden of tuberculosis. The Philippines has the fourth highest tuberculosis incidence rate in the world. The country accounted for 7.0% of all incident cases of tuberculosis globally in 2022. There are 638 new cases of tuberculosis per 100,000 population in the Philippines for the same year. Compare this with the worldwide incidence of 133 per 100,000 population and a western Pacific regional incidence of 96 per 100,000 population. ¹ The patient denies a history of HIV infection or any risky sexual behavior. He denies chronic steroid intake, and he is not diabetic.

Dr Mark Anthony Sandoval: How was he worked up? What were the results of the diagnostic tests?

Dr Carisa Mariella Paraz: Throughout the course of his illness, the patient self-performed 3 separate rapid antigen tests for SARS-CoV-2 via nasopharyngeal swabs—all were negative. Complete blood count showed leukocytosis with neutrophilic predominance (white blood cells, 11.78×10⁹/mL, 79.60% neutrophils). Sputum microscopy for acid-fast bacilli (AFB) was done twice—both negative. Mycobacterium tuberculosis was not detected on sputum using GeneXpert (Cepheid Inc, Sunnyvale, CA), an automated molecular test for tuberculosis. Diabetes was ruled out on the basis of a fasting glucose concentration of 5.52 mmol·L^–1 and an hemoglobin A1C level of 4.10%. Chest x-ray (Figure 1) revealed an ill-defined, thick-walled lucency in the right suprahilar region. A follow-up chest computed tomography scan (Figure 2) revealed an irregularly shaped cavity formation in the inferior portion of the posterior segment of the right upper lobe extending to the adjacent portion of the superior basal segment of the right lower lobe, measuring 2.5 cm anteroposteriorly by 4.1 cm wide.

Figure 1.

Chest x-ray showing an ill-defined, thick-walled lucency in the right suprahilar region.

Figure 2.

Chest computed tomography scan showing an irregularly shaped cavity formation in the inferior portion of the posterior segment of the right upper lobe extending to the adjacent portion of the superior basal segment of the right lower lobe measuring 2.5×4.1 cm (APxW).

Dr Mark Anthony Sandoval: The patient’s symptoms and the finding of a cavitary lesion in the right lung indeed point to tuberculosis. The negative GeneXpert result, however, now makes tuberculosis less likely. Among patients who are sputum AFB+, the sensitivity of this test is 98.2%. For individuals who are sputum AFB–, the sensitivity is 72.5%. ² Were you able to elicit more information in the clinical history to have an alternate diagnosis?

Dr Carisa Mariella Paraz: The patient mentioned that he was on a holiday trip to the coastal village of Basdaku, Moalboal town, on the island of Cebu in central Philippines. He remembered that 2 d prior to the onset of symptoms, he went recreational free diving ∼50 ms from the shore. He aspirated seawater while using a defective rented snorkel. While underwater and ascending to the surface, he “inhaled seawater, suppressed the urge to cough or inhale while underwater, and held his breath until he surfaced.” He coughed out a “mouthful of seawater.” He is a licensed open-water diver and has gone free diving on numerous occasions at various sites, but this is the first time that he had aspirated seawater.

Dr Mark Anthony Sandoval: With this additional information, the diagnosis is now bacterial lung abscess from aspiration of seawater. Do we have microbiologic confirmation of this condition? How did we procced in treating him?

Dr Enrick Joshua Cruz: The patient was initially prescribed a 7-d course of moxifloxacin 500 mg bid. However, sputum culture eventually showed heavy growth of Klebsiella pneumoniae sp pneumoniae (KPN), which was resistant to the quinolone ciprofloxacin. Hence, moxifloxacin was shifted to oral cefuroxime, to which the isolate was susceptible. Our final diagnosis: KPN bacterial lung abscess from aspiration of seawater during recreational free diving.

Dr Mark Anthony Sandoval: How did the patient respond to oral cefuroxime?

Dr Carisa Mariella Paraz: The patient completed 14 d of oral cefuroxime 500 mg bid, which led to complete resolution of all his symptoms. Chest x-ray 5 mo after treatment (Figure 3) showed resolution of the lung abscess. Because the patient improved clinically and remained symptoms-free during this time, it was felt that a repeat computed tomography scan was unnecessary.

Figure 3.

Repeat chest x-ray done 5 mo after completion of treatment showing resolution of the lung abscess.

Dr Mark Anthony Sandoval: It is fortunate that the patient responded to oral antibiotics and did not require drainage of the abscess. This case is worth reporting and discussing because it highlights the health risk among travelers or tourists who engage in recreational free diving if there is accidental aspiration of seawater.

Dr Carisa Mariella Paraz: Do we have any information about whether KPN grows in the marine coastal areas of Cebu, Philippines, particularly in regions frequented by travelers/tourists?

Dr Mark Anthony Sandoval: The Philippines is an archipelago with beaches among its tourist attractions. Cebu is a known destination for swimming, bathing, snorkeling, and diving. The presence of coliform bacteria in bodies of water indicates the presence of waste from humans and other animals that can cause disease. Coliforms are bacteria from the family Enterobacteriaceae, which includes Escherichia coli, Enterobacter, Klebsiella, and Citrobacter. The Environmental Management Bureau performs monthly coliform counts of the coastal waters. The regulatory guideline for coastal waters used for fisheries, tourist zones, and primary contact recreation areas (ie, diving, snorkeling, swimming, and bathing) is <100 most probable number per 100 mL. In the village of Basdaku, in Moalbal, Cebu, where our patient's resort was located, the fecal coliform count from 3 sites in January 2020 were 130, 31, and 23 most probable number per 100 mL. Note that one of the samples exceeded the regulatory guideline at that time. Isolation of coliform bacteria fluctuates with the season, with the counts being highest during the wet season of September to December. Our patient was in that location in January 2023, so the data for January 2020 (the latest available published data) can be extrapolated to the time that he was diving. ³

Dr Enrick Joshua Cruz: What are the factors that contribute to the presence of coliform bacteria in these waters?

Dr Mark Anthony Sandoval: Factors that contribute to a high coliform level include discharge from failed sewage treatment plants, feces, population of swimmers, number of boats, improper waste management from coastal households, and stormwater runoff, among others. It is comforting to know that the local governmental unit has already conducted meetings with stakeholders on how to improve the water quality as tourism increases locally. ⁴

Dr Mark Anthony Sandoval: Have we collected samples of seawater from the area where the patient did free diving to prove that KPN thrives in it?

Dr Carisa Mariella Paraz: A limitation of this report is that we have not collected seawater from the locale to test whether KPN is indeed present. The Environmental Management Bureau report mentioned earlier dealt with coliform bacteria in general and not KPN in particular. Prospectively collecting a sample with the aim of isolating KPN is impractical to do because the residence of the patient and where he was seen by our team (Luzon Island) and Cebu, where he went for holiday, are 570 km apart.

Dr Mark Anthony Sandoval: KPN was first described by Carl Friedlander in 1882 after this bacterium was isolated from patients who died of pneumonia. Hence, the disease it caused is also known as Friedlander's pneumonia. Alcoholism and diabetes are risk factors, both of which were not present in our patient. ⁴ This encapsulated gram-negative bacillus survives in marine, distilled, tap, and natural spring waters. ⁵ KPN is termed a survivor because it is known to survive tropical marine environments. ⁶

Dr Enrick Joshua Cruz: Is this problem of having coliform bacteria in marine waters unique to the Philippines, or is it a global concern?

Dr Mark Anthony Sandoval: KPN has been isolated from coastal waters in various parts of the world, such as in Galveston, Texas, Gulf of Annaba in the Mediterranean, eastern Adriatic Sea in Croatia, Baltic Sea in Germany, and the Upper Gulf of Thailand.^7–11 In the Philippines, extended-spectrum beta-lactamase-producing KPN has been isolated in aquacultures. Among 169 isolates from Southeast Asia, 2.37% came from the Philippines. ¹² Thus, this problem of having potentially pathogenic bacteria in bodies of water used for recreation is not unique to the Philippines but is a global concern.

Dr Enrick Joshua Cruz: Drowning at sea and aspiration of seawater have the same pathophysiologic mechanism of introducing seawater into the respiratory tract, albeit with varying magnitudes. The aspiration of seawater by our patient could be considered a subdued form of drowning. In a study of seawater drowning, patients developed pneumonia, and among the most common isolates were Enterobacteriaceae (Enterobacter spp, Klebsiella spp, and E coli). ¹³ Immersion in seawater during a tsunami is another mechanism by which microorganisms can be introduced into the respiratory tract. Necrotizing pneumonia with cavitation was reported in 6 to 10 patients in Banda Aceh, Indonesia, after the December 2004 tsunami in the Indian Ocean. The aspiration of seawater in these cases, however, was from a natural disaster, whereas the case we are reporting is in the context of recreational diving. ¹⁴ Is aspiration of seawater during recreational free diving a common occurrence? Have there been reports of similar cases?

Dr Mark Anthony Sandoval: Literature search using PubMed revealed only 1 other report of lung abscess from aspiration of seawater. A case report from Spain described 2 patients. The first aspirated seawater while bathing at sea, and the second aspirated seawater while diving beside his boat. The places where they dove were in the ports and anchorages where their boats were docked. Hence, their diving could be said to be nonrecreational. This distinction with regard to the context of where aspiration of seawater occurred has to be emphasized because the patient we report in this case came to sea for recreational purposes in an area dedicated to leisure activities and not in ports or anchorages where boats dock, which are expected to be more polluted. Symptoms of fever, hemoptysis, and foul-smelling sputum in the Spanish cases were similar to those in our patient. Similarly, tuberculosis also was the first impression in 1 of the cases. What was different is that microbiologic examination was polymicrobial for both Spanish cases, whereas only 1 organism was isolated from our patient. Also, both patients in this Spanish report required surgery, whereas our patient responded to oral antibiotics alone. ¹⁵

Conclusion

In the Philippines, tuberculosis should be the first consideration in a patient with cough for at least 2 wk, constitutional symptoms of low-grade fever and night sweats, and pinkish or reddish sputum suggestive of hemoptysis. The cavitary lesion on x-ray also was compatible with tuberculosis. With GeneXpert having a high sensitivity, this diagnosis was easily ruled out. It was fortunate that the sputum culture grew KPN as early as 24 h after incubation. The distinct description of foul-tasting sputum also favors a bacterial lung abscess over tuberculosis, with this symptom being observed in 67.5% of patients with lung abscess. ¹⁶ In addition, the patient's description of “pinkish to reddish sputum with the consistency of yoghurt” can be said to be typical for KPN because this was a similar finding in a patient described as having “currant- or berry jelly-like” sputum and subsequently diagnosed with Friedlander's pneumonia. ¹⁷ Because of our patient's vivid description of his symptoms plus the rapid turnaround of diagnostic tests, the diagnosis was clinched, and appropriate treatment was instituted promptly, avoiding a catastrophic outcome for this serious infection.