Nosocomial pulmonary infections at Peltier Hospital, Djibouti

Nosocomial pulmonary infections are a major public health problem. The retrospective study was carried out on medical records of 140 patients aged 59.4±32.2, 0.29 (mean ± sd, SEM) years, admitted at Peltier hospital, Djibouti, between May 5, 2018 and April 30, 2020, and who developed nosocomial pulmonary infections after 48 h of admission. The objective was to establish incidence of nosocomial pulmonary infections, identify the causative agents, and establish appropriate antimicrobial regimens to improve case management. Tracheobronchial secretions were cultured on appropriate culture media and antimicrobial susceptibility testing done on bacteria isolates. About 9(6.4%) cultures were sterile, 21(15%) and 110(78.6%) had Candida albicans and polymicrobial infection respectively. The study established that 80.9% of nosocomial pneumonia during the study period was due to gram negative bacilli, while 14.6% was due to Staphylococcus aureus . Cefotaxime and Colistin were the drugs of choice for P. aeruginosa and A. baumannii respectively.


INTRODUCTION
Nosocomial infections are acquired infections during hospital stay that were neither present nor in incubation at the time of patient admission (Pan American Health Organization, 2018). The frequency, cost of diagnosis and treatment are a major public health concern worldwide (Pooja et al., 2016;Saravanan et al., 2018). Causative agents are often resistant to available antibiotics and their prognosis is grave (Haroon et al., 2020;Hassuna et al., 2020). Infections caused by multidrug resistant gram negative bacteria are a major public health problem in developing countries (Adesola et al., 2020;Ali et al., 2020;Aworh et al., 2019;Horsefall et al., 2017). Several studies have been carried out to take stock of healthcarerelated infections in many countries (Amulioto et al., 2020;Oli et al., 2017;Schuts et al., 2016).

MATERIALS AND METHODS
Medical records of 140 in-patients whom within the study period developed pulmonary infections, demonstrated by recent onset of purulent tracheal secretions, recent fever, leukocytosis, dyspnea and positive cultures for respiratory infections, in the absence of other causes after 48 h of admission were reviewed and considered for the retrospective study. Tracheal aspirate specimens collected using protected specimen brush (PSB) following a clinical diagnosis of pneumonia and prior to initiation of antimicrobial therapy, had been collected and cultured on Blood agar, Chocolate agar, MacConkey and Sabouraud media incubated overnight at 37°C and room temperature overnight respectively.
Standard antibacterial susceptibility testing was assessed on Muller-Hinton agar according to the Kirby-Bauer method using standardized inoculum of isolated bacteria colonies. The antibacterial susceptibility test interpretive criteria and quality control performance standards for antimicrobial testing was used to bacterial isolates either as, susceptible, intermediate or resistant (CLSI, 2013). Resistance percentage was calculated where isolates for susceptibility to specific antibiotics was ≥ 30 and tabulated in Table 1.
Streptococcus faecalis ATCC 29212 control strain was used against Cotrimoxazole disk for batch-to-batch validation of Muller-Hinton agar during the study period. Batch-to-batch validation of new susceptibility disks was tested against Staphylococcus aureus ATCC 25922, Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853 and the zones of inhibitions were compared with the quality control limits on Muller-Hinton agar for monitoring antibiotic susceptibility testing.

RESULTS AND DISCUSSION
The retrospective study was carried out on medical records of 140 patients aged 59.4±32.2, 0.29 (mean ± sd, SEM) years, admitted at Peltier hospital, Djibouti, between May 5, 2018 and April 30, 2020, who developed nosocomial pulmonary infections after 48 h of admission. Bacterial percentage resistances responsible for nosocomial pulmonary infections are tabulated in Table  1. From the study, 9(6.4%) cultures were sterile, 21(15%) and 110(78.6%) had Candida albicans and polymicrobial infection respectively. Also, 80.9% of nosocomial pneumonia during the study period was due to gram negative bacilli, while 14.6% was due to methicillin resistant Staphylococcus aureus. The microbiological examination revealed 9 organisms responsible for nosocomial infection in infected patients: Escherichia coli, P. aeruginosa, S. aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Enterobacter cloacae, Proteus mirabilis, Streptococcus pneumoniae and Klebsiella oxytoca.
The phenotypes of the gram negative bacilli were categorized into: Carbapenem-resistant E. coli (19%), Carbapenem-resistant K. pneumoniae (13%) and Carbapenem-non-susceptible P. aeruginosa (15.5%). Cefotaxime and Colistin were the drugs of choice for managing nosocomial pulmonary infections at Peltier hospital. The study recommended antimicrobial stewardship through establishment of an infection control committee to reduce microbial resistance and decrease the spread of infection caused by multidrug resistant organisms. Infections caused by multidrug resistant gram negative bacteria are a major public health problem in developing countries (Djoman et al., 2020;Falgenhauer et al., 2019;Founou et al., 2018). Several studies have been carried out to take stock of healthcare-related infections in many countries (Bekoe et al., 2020;Herawati et al., 2017;Karanika et al., 2016).

Conclusion
Cefotaxime and Colistin are the drugs of choice for managing nosocomial pulmonary infections at Peltier hospital. Antimicrobial stewardship is necessary to safeguard the effectiveness of the drugs of choice. There is a need for perspective study on nosocomial infections in the hospital to identify the general and upcoming antimicrobial resistant phenotypes and to continually monitor antimicrobial resistance.